diff --git a/deps/v8/BUILD.gn b/deps/v8/BUILD.gn
index 059ee07086248d..3eb7fc73eb9aae 100644
--- a/deps/v8/BUILD.gn
+++ b/deps/v8/BUILD.gn
@@ -1077,6 +1077,8 @@ source_set("v8_base") {
     "src/splay-tree.h",
     "src/splay-tree-inl.h",
     "src/snapshot/snapshot.h",
+    "src/startup-data-util.h",
+    "src/startup-data-util.cc",
     "src/string-builder.cc",
     "src/string-builder.h",
     "src/string-search.cc",
@@ -1678,8 +1680,6 @@ if ((current_toolchain == host_toolchain && v8_toolset_for_d8 == "host") ||
     sources = [
       "src/d8.cc",
       "src/d8.h",
-      "src/startup-data-util.h",
-      "src/startup-data-util.cc",
     ]
 
     configs -= [ "//build/config/compiler:chromium_code" ]
diff --git a/deps/v8/include/v8-version.h b/deps/v8/include/v8-version.h
index f6f62d736a373b..a2dc5b0db6b283 100644
--- a/deps/v8/include/v8-version.h
+++ b/deps/v8/include/v8-version.h
@@ -11,7 +11,7 @@
 #define V8_MAJOR_VERSION 4
 #define V8_MINOR_VERSION 5
 #define V8_BUILD_NUMBER 103
-#define V8_PATCH_LEVEL 24
+#define V8_PATCH_LEVEL 30
 
 // Use 1 for candidates and 0 otherwise.
 // (Boolean macro values are not supported by all preprocessors.)
diff --git a/deps/v8/include/v8.h b/deps/v8/include/v8.h
index 6e1db3a581f5c7..c651b7cd09ba19 100644
--- a/deps/v8/include/v8.h
+++ b/deps/v8/include/v8.h
@@ -6247,6 +6247,25 @@ class V8_EXPORT V8 {
    */
   static bool InitializeICU(const char* icu_data_file = NULL);
 
+  /**
+   * Initialize the external startup data. The embedder only needs to
+   * invoke this method when external startup data was enabled in a build.
+   *
+   * If V8 was compiled with the startup data in an external file, then
+   * V8 needs to be given those external files during startup. There are
+   * three ways to do this:
+   * - InitializeExternalStartupData(const char*)
+   *   This will look in the given directory for files "natives_blob.bin"
+   *   and "snapshot_blob.bin" - which is what the default build calls them.
+   * - InitializeExternalStartupData(const char*, const char*)
+   *   As above, but will directly use the two given file names.
+   * - Call SetNativesDataBlob, SetNativesDataBlob.
+   *   This will read the blobs from the given data structures and will
+   *   not perform any file IO.
+   */
+  static void InitializeExternalStartupData(const char* directory_path);
+  static void InitializeExternalStartupData(const char* natives_blob,
+                                            const char* snapshot_blob);
   /**
    * Sets the v8::Platform to use. This should be invoked before V8 is
    * initialized.
diff --git a/deps/v8/samples/hello-world.cc b/deps/v8/samples/hello-world.cc
index 8be5a31fca4a74..3b952d816b9b96 100644
--- a/deps/v8/samples/hello-world.cc
+++ b/deps/v8/samples/hello-world.cc
@@ -25,6 +25,7 @@ class ArrayBufferAllocator : public v8::ArrayBuffer::Allocator {
 int main(int argc, char* argv[]) {
   // Initialize V8.
   V8::InitializeICU();
+  V8::InitializeExternalStartupData(argv[0]);
   Platform* platform = platform::CreateDefaultPlatform();
   V8::InitializePlatform(platform);
   V8::Initialize();
diff --git a/deps/v8/samples/process.cc b/deps/v8/samples/process.cc
index a62950a76ab4b7..6f7a47f1b01eb9 100644
--- a/deps/v8/samples/process.cc
+++ b/deps/v8/samples/process.cc
@@ -686,6 +686,7 @@ void PrintMap(map<string, string>* m) {
 
 int main(int argc, char* argv[]) {
   v8::V8::InitializeICU();
+  v8::V8::InitializeExternalStartupData(argv[0]);
   v8::Platform* platform = v8::platform::CreateDefaultPlatform();
   v8::V8::InitializePlatform(platform);
   v8::V8::Initialize();
diff --git a/deps/v8/samples/shell.cc b/deps/v8/samples/shell.cc
index 3a743d6c13bebe..bd621c5465750e 100644
--- a/deps/v8/samples/shell.cc
+++ b/deps/v8/samples/shell.cc
@@ -75,6 +75,7 @@ class ShellArrayBufferAllocator : public v8::ArrayBuffer::Allocator {
 
 int main(int argc, char* argv[]) {
   v8::V8::InitializeICU();
+  v8::V8::InitializeExternalStartupData(argv[0]);
   v8::Platform* platform = v8::platform::CreateDefaultPlatform();
   v8::V8::InitializePlatform(platform);
   v8::V8::Initialize();
diff --git a/deps/v8/src/api.cc b/deps/v8/src/api.cc
index 5ff8ccbae5145c..593aea641b2bf3 100644
--- a/deps/v8/src/api.cc
+++ b/deps/v8/src/api.cc
@@ -49,6 +49,7 @@
 #include "src/simulator.h"
 #include "src/snapshot/natives.h"
 #include "src/snapshot/snapshot.h"
+#include "src/startup-data-util.h"
 #include "src/unicode-inl.h"
 #include "src/v8threads.h"
 #include "src/version.h"
@@ -5398,11 +5399,23 @@ HeapObjectStatistics::HeapObjectStatistics()
       object_count_(0),
       object_size_(0) {}
 
+
 bool v8::V8::InitializeICU(const char* icu_data_file) {
   return i::InitializeICU(icu_data_file);
 }
 
 
+void v8::V8::InitializeExternalStartupData(const char* directory_path) {
+  i::InitializeExternalStartupData(directory_path);
+}
+
+
+void v8::V8::InitializeExternalStartupData(const char* natives_blob,
+                                           const char* snapshot_blob) {
+  i::InitializeExternalStartupData(natives_blob, snapshot_blob);
+}
+
+
 const char* v8::V8::GetVersion() {
   return i::Version::GetVersion();
 }
diff --git a/deps/v8/src/arm/assembler-arm.cc b/deps/v8/src/arm/assembler-arm.cc
index 96bdf79facedeb..481a3b5ceddebb 100644
--- a/deps/v8/src/arm/assembler-arm.cc
+++ b/deps/v8/src/arm/assembler-arm.cc
@@ -128,7 +128,8 @@ void CpuFeatures::ProbeImpl(bool cross_compile) {
   if (FLAG_enable_32dregs && cpu.has_vfp3_d32()) supported_ |= 1u << VFP32DREGS;
 
   if (cpu.implementer() == base::CPU::NVIDIA &&
-      cpu.variant() == base::CPU::NVIDIA_DENVER) {
+      cpu.variant() == base::CPU::NVIDIA_DENVER &&
+      cpu.part() <= base::CPU::NVIDIA_DENVER_V10) {
     supported_ |= 1u << COHERENT_CACHE;
   }
 #endif
diff --git a/deps/v8/src/arm64/assembler-arm64.cc b/deps/v8/src/arm64/assembler-arm64.cc
index 5445fe1a1b19a9..f27d3b97b0fb05 100644
--- a/deps/v8/src/arm64/assembler-arm64.cc
+++ b/deps/v8/src/arm64/assembler-arm64.cc
@@ -53,7 +53,8 @@ void CpuFeatures::ProbeImpl(bool cross_compile) {
   // Probe for runtime features
   base::CPU cpu;
   if (cpu.implementer() == base::CPU::NVIDIA &&
-      cpu.variant() == base::CPU::NVIDIA_DENVER) {
+      cpu.variant() == base::CPU::NVIDIA_DENVER &&
+      cpu.part() <= base::CPU::NVIDIA_DENVER_V10) {
     supported_ |= 1u << COHERENT_CACHE;
   }
 }
diff --git a/deps/v8/src/base/cpu.h b/deps/v8/src/base/cpu.h
index f6c5a8506a0058..1dc0a91f650112 100644
--- a/deps/v8/src/base/cpu.h
+++ b/deps/v8/src/base/cpu.h
@@ -59,6 +59,9 @@ class CPU final {
   static const int ARM_CORTEX_A12 = 0xc0c;
   static const int ARM_CORTEX_A15 = 0xc0f;
 
+  // Denver-specific part code
+  static const int NVIDIA_DENVER_V10 = 0x002;
+
   // PPC-specific part codes
   enum {
     PPC_POWER5,
diff --git a/deps/v8/src/d8.cc b/deps/v8/src/d8.cc
index 7db6f3ed9e4420..45bf33167fd014 100644
--- a/deps/v8/src/d8.cc
+++ b/deps/v8/src/d8.cc
@@ -50,10 +50,6 @@
 #include "src/v8.h"
 #endif  // !V8_SHARED
 
-#ifdef V8_USE_EXTERNAL_STARTUP_DATA
-#include "src/startup-data-util.h"
-#endif  // V8_USE_EXTERNAL_STARTUP_DATA
-
 #if !defined(_WIN32) && !defined(_WIN64)
 #include <unistd.h>  // NOLINT
 #else
@@ -2316,10 +2312,12 @@ int Shell::Main(int argc, char* argv[]) {
   g_platform = v8::platform::CreateDefaultPlatform();
   v8::V8::InitializePlatform(g_platform);
   v8::V8::Initialize();
-#ifdef V8_USE_EXTERNAL_STARTUP_DATA
-  v8::StartupDataHandler startup_data(argv[0], options.natives_blob,
-                                      options.snapshot_blob);
-#endif
+  if (options.natives_blob || options.snapshot_blob) {
+    v8::V8::InitializeExternalStartupData(options.natives_blob,
+                                          options.snapshot_blob);
+  } else {
+    v8::V8::InitializeExternalStartupData(argv[0]);
+  }
   SetFlagsFromString("--trace-hydrogen-file=hydrogen.cfg");
   SetFlagsFromString("--trace-turbo-cfg-file=turbo.cfg");
   SetFlagsFromString("--redirect-code-traces-to=code.asm");
diff --git a/deps/v8/src/d8.gyp b/deps/v8/src/d8.gyp
index 548459a7901463..e92a3219908f90 100644
--- a/deps/v8/src/d8.gyp
+++ b/deps/v8/src/d8.gyp
@@ -50,8 +50,6 @@
       'sources': [
         'd8.h',
         'd8.cc',
-        'startup-data-util.h',
-        'startup-data-util.cc'
       ],
       'conditions': [
         [ 'want_separate_host_toolset==1', {
diff --git a/deps/v8/src/heap/heap.cc b/deps/v8/src/heap/heap.cc
index 47717c162b2ec5..3d953730013252 100644
--- a/deps/v8/src/heap/heap.cc
+++ b/deps/v8/src/heap/heap.cc
@@ -4867,19 +4867,6 @@ void Heap::ReduceNewSpaceSize() {
 }
 
 
-void Heap::FinalizeIncrementalMarkingIfComplete(const char* comment) {
-  if (FLAG_overapproximate_weak_closure &&
-      (incremental_marking()->IsReadyToOverApproximateWeakClosure() ||
-       (!incremental_marking()->weak_closure_was_overapproximated() &&
-        mark_compact_collector_.marking_deque()->IsEmpty()))) {
-    OverApproximateWeakClosure(comment);
-  } else if (incremental_marking()->IsComplete() ||
-             (mark_compact_collector_.marking_deque()->IsEmpty())) {
-    CollectAllGarbage(kNoGCFlags, comment);
-  }
-}
-
-
 bool Heap::TryFinalizeIdleIncrementalMarking(
     double idle_time_in_ms, size_t size_of_objects,
     size_t final_incremental_mark_compact_speed_in_bytes_per_ms) {
diff --git a/deps/v8/src/heap/heap.h b/deps/v8/src/heap/heap.h
index 38166439eadebe..4c9e3ad1448032 100644
--- a/deps/v8/src/heap/heap.h
+++ b/deps/v8/src/heap/heap.h
@@ -852,8 +852,6 @@ class Heap {
       intptr_t step_size_in_bytes, double deadline_in_ms,
       IncrementalMarking::StepActions step_actions);
 
-  void FinalizeIncrementalMarkingIfComplete(const char* comment);
-
   inline void increment_scan_on_scavenge_pages() {
     scan_on_scavenge_pages_++;
     if (FLAG_gc_verbose) {
@@ -1644,8 +1642,6 @@ class Heap {
   bool HasHighFragmentation();
   bool HasHighFragmentation(intptr_t used, intptr_t committed);
 
-  bool ShouldOptimizeForMemoryUsage() { return optimize_for_memory_usage_; }
-
  protected:
   // Methods made available to tests.
 
diff --git a/deps/v8/src/heap/memory-reducer.cc b/deps/v8/src/heap/memory-reducer.cc
index e226f09a04ad88..df827bae29e48c 100644
--- a/deps/v8/src/heap/memory-reducer.cc
+++ b/deps/v8/src/heap/memory-reducer.cc
@@ -44,35 +44,12 @@ void MemoryReducer::NotifyTimer(const Event& event) {
   if (state_.action == kRun) {
     DCHECK(heap()->incremental_marking()->IsStopped());
     DCHECK(FLAG_incremental_marking);
+    heap()->StartIdleIncrementalMarking();
     if (FLAG_trace_gc_verbose) {
       PrintIsolate(heap()->isolate(), "Memory reducer: started GC #%d\n",
                    state_.started_gcs);
     }
-    if (heap()->ShouldOptimizeForMemoryUsage()) {
-      // Do full GC if memory usage has higher priority than latency. This is
-      // important for background tabs that do not send idle notifications.
-      heap()->CollectAllGarbage(Heap::kReduceMemoryFootprintMask,
-                                "memory reducer");
-    } else {
-      heap()->StartIdleIncrementalMarking();
-    }
   } else if (state_.action == kWait) {
-    if (!heap()->incremental_marking()->IsStopped() &&
-        heap()->ShouldOptimizeForMemoryUsage()) {
-      // Make progress with pending incremental marking if memory usage has
-      // higher priority than latency. This is important for background tabs
-      // that do not send idle notifications.
-      const int kIncrementalMarkingDelayMs = 500;
-      double deadline = heap()->MonotonicallyIncreasingTimeInMs() +
-                        kIncrementalMarkingDelayMs;
-      heap()->AdvanceIncrementalMarking(
-          0, deadline, i::IncrementalMarking::StepActions(
-                           i::IncrementalMarking::NO_GC_VIA_STACK_GUARD,
-                           i::IncrementalMarking::FORCE_MARKING,
-                           i::IncrementalMarking::FORCE_COMPLETION));
-      heap()->FinalizeIncrementalMarkingIfComplete(
-          "Memory reducer: finalize incremental marking");
-    }
     // Re-schedule the timer.
     ScheduleTimer(state_.next_gc_start_ms - event.time_ms);
     if (FLAG_trace_gc_verbose) {
diff --git a/deps/v8/src/preparser.h b/deps/v8/src/preparser.h
index 9ebc132d92b497..d9ef1ea31ec515 100644
--- a/deps/v8/src/preparser.h
+++ b/deps/v8/src/preparser.h
@@ -2939,6 +2939,7 @@ ParserBase<Traits>::ParseConditionalExpression(bool accept_IN,
   ExpressionT expression =
       this->ParseBinaryExpression(4, accept_IN, classifier, CHECK_OK);
   if (peek() != Token::CONDITIONAL) return expression;
+  ArrowFormalParametersUnexpectedToken(classifier);
   BindingPatternUnexpectedToken(classifier);
   Consume(Token::CONDITIONAL);
   // In parsing the first assignment expression in conditional
@@ -2964,6 +2965,7 @@ ParserBase<Traits>::ParseBinaryExpression(int prec, bool accept_IN,
     // prec1 >= 4
     while (Precedence(peek(), accept_IN) == prec1) {
       BindingPatternUnexpectedToken(classifier);
+      ArrowFormalParametersUnexpectedToken(classifier);
       Token::Value op = Next();
       Scanner::Location op_location = scanner()->location();
       int pos = position();
@@ -3026,6 +3028,7 @@ ParserBase<Traits>::ParseUnaryExpression(ExpressionClassifier* classifier,
   Token::Value op = peek();
   if (Token::IsUnaryOp(op)) {
     BindingPatternUnexpectedToken(classifier);
+    ArrowFormalParametersUnexpectedToken(classifier);
 
     op = Next();
     int pos = position();
@@ -3048,6 +3051,7 @@ ParserBase<Traits>::ParseUnaryExpression(ExpressionClassifier* classifier,
     return this->BuildUnaryExpression(expression, op, pos, factory());
   } else if (Token::IsCountOp(op)) {
     BindingPatternUnexpectedToken(classifier);
+    ArrowFormalParametersUnexpectedToken(classifier);
     op = Next();
     Scanner::Location lhs_location = scanner()->peek_location();
     ExpressionT expression = this->ParseUnaryExpression(classifier, CHECK_OK);
@@ -3080,6 +3084,7 @@ ParserBase<Traits>::ParsePostfixExpression(ExpressionClassifier* classifier,
   if (!scanner()->HasAnyLineTerminatorBeforeNext() &&
       Token::IsCountOp(peek())) {
     BindingPatternUnexpectedToken(classifier);
+    ArrowFormalParametersUnexpectedToken(classifier);
 
     expression = this->CheckAndRewriteReferenceExpression(
         expression, lhs_location, MessageTemplate::kInvalidLhsInPostfixOp,
@@ -3111,6 +3116,7 @@ ParserBase<Traits>::ParseLeftHandSideExpression(
     switch (peek()) {
       case Token::LBRACK: {
         BindingPatternUnexpectedToken(classifier);
+        ArrowFormalParametersUnexpectedToken(classifier);
         Consume(Token::LBRACK);
         int pos = position();
         ExpressionT index = ParseExpression(true, classifier, CHECK_OK);
@@ -3121,6 +3127,7 @@ ParserBase<Traits>::ParseLeftHandSideExpression(
 
       case Token::LPAREN: {
         BindingPatternUnexpectedToken(classifier);
+        ArrowFormalParametersUnexpectedToken(classifier);
 
         if (is_strong(language_mode()) && this->IsIdentifier(result) &&
             this->IsEval(this->AsIdentifier(result))) {
@@ -3172,6 +3179,7 @@ ParserBase<Traits>::ParseLeftHandSideExpression(
 
       case Token::PERIOD: {
         BindingPatternUnexpectedToken(classifier);
+        ArrowFormalParametersUnexpectedToken(classifier);
         Consume(Token::PERIOD);
         int pos = position();
         IdentifierT name = ParseIdentifierName(CHECK_OK);
@@ -3184,6 +3192,7 @@ ParserBase<Traits>::ParseLeftHandSideExpression(
       case Token::TEMPLATE_SPAN:
       case Token::TEMPLATE_TAIL: {
         BindingPatternUnexpectedToken(classifier);
+        ArrowFormalParametersUnexpectedToken(classifier);
         result = ParseTemplateLiteral(result, position(), classifier, CHECK_OK);
         break;
       }
@@ -3221,6 +3230,7 @@ ParserBase<Traits>::ParseMemberWithNewPrefixesExpression(
 
   if (peek() == Token::NEW) {
     BindingPatternUnexpectedToken(classifier);
+    ArrowFormalParametersUnexpectedToken(classifier);
     Consume(Token::NEW);
     int new_pos = position();
     ExpressionT result = this->EmptyExpression();
@@ -3274,6 +3284,7 @@ ParserBase<Traits>::ParseMemberExpression(ExpressionClassifier* classifier,
   ExpressionT result = this->EmptyExpression();
   if (peek() == Token::FUNCTION) {
     BindingPatternUnexpectedToken(classifier);
+    ArrowFormalParametersUnexpectedToken(classifier);
 
     Consume(Token::FUNCTION);
     int function_token_position = position();
@@ -3523,6 +3534,7 @@ ParserBase<Traits>::ParseMemberExpressionContinuation(
     switch (peek()) {
       case Token::LBRACK: {
         BindingPatternUnexpectedToken(classifier);
+        ArrowFormalParametersUnexpectedToken(classifier);
 
         Consume(Token::LBRACK);
         int pos = position();
@@ -3536,6 +3548,7 @@ ParserBase<Traits>::ParseMemberExpressionContinuation(
       }
       case Token::PERIOD: {
         BindingPatternUnexpectedToken(classifier);
+        ArrowFormalParametersUnexpectedToken(classifier);
 
         Consume(Token::PERIOD);
         int pos = position();
@@ -3550,6 +3563,7 @@ ParserBase<Traits>::ParseMemberExpressionContinuation(
       case Token::TEMPLATE_SPAN:
       case Token::TEMPLATE_TAIL: {
         BindingPatternUnexpectedToken(classifier);
+        ArrowFormalParametersUnexpectedToken(classifier);
         int pos;
         if (scanner()->current_token() == Token::IDENTIFIER) {
           pos = position();
diff --git a/deps/v8/src/startup-data-util.cc b/deps/v8/src/startup-data-util.cc
index 1b2f7ed7e95129..92c4b5b3e9820d 100644
--- a/deps/v8/src/startup-data-util.cc
+++ b/deps/v8/src/startup-data-util.cc
@@ -8,66 +8,41 @@
 #include <string.h>
 
 #include "src/base/logging.h"
+#include "src/base/platform/platform.h"
 
 
 namespace v8 {
+namespace internal {
 
 #ifdef V8_USE_EXTERNAL_STARTUP_DATA
 
-StartupDataHandler::StartupDataHandler(const char* exec_path,
-                                       const char* natives_blob,
-                                       const char* snapshot_blob) {
-  // If we have (at least one) explicitly given blob, use those.
-  // If not, use the default blob locations next to the d8 binary.
-  if (natives_blob || snapshot_blob) {
-    LoadFromFiles(natives_blob, snapshot_blob);
-  } else {
-    char* natives;
-    char* snapshot;
-    LoadFromFiles(RelativePath(&natives, exec_path, "natives_blob.bin"),
-                  RelativePath(&snapshot, exec_path, "snapshot_blob.bin"));
+namespace {
 
-    free(natives);
-    free(snapshot);
-  }
-}
+v8::StartupData g_natives;
+v8::StartupData g_snapshot;
 
 
-StartupDataHandler::~StartupDataHandler() {
-  delete[] natives_.data;
-  delete[] snapshot_.data;
+void ClearStartupData(v8::StartupData* data) {
+  data->data = nullptr;
+  data->raw_size = 0;
 }
 
 
-char* StartupDataHandler::RelativePath(char** buffer, const char* exec_path,
-                                       const char* name) {
-  DCHECK(exec_path);
-  const char* last_slash = strrchr(exec_path, '/');
-  if (last_slash) {
-    int after_slash = static_cast<int>(last_slash - exec_path + 1);
-    int name_length = static_cast<int>(strlen(name));
-    *buffer = reinterpret_cast<char*>(calloc(after_slash + name_length + 1, 1));
-    strncpy(*buffer, exec_path, after_slash);
-    strncat(*buffer, name, name_length);
-  } else {
-    *buffer = strdup(name);
-  }
-  return *buffer;
+void DeleteStartupData(v8::StartupData* data) {
+  delete[] data->data;
+  ClearStartupData(data);
 }
 
 
-void StartupDataHandler::LoadFromFiles(const char* natives_blob,
-                                       const char* snapshot_blob) {
-  Load(natives_blob, &natives_, v8::V8::SetNativesDataBlob);
-  Load(snapshot_blob, &snapshot_, v8::V8::SetSnapshotDataBlob);
+void FreeStartupData() {
+  DeleteStartupData(&g_natives);
+  DeleteStartupData(&g_snapshot);
 }
 
 
-void StartupDataHandler::Load(const char* blob_file,
-                              v8::StartupData* startup_data,
-                              void (*setter_fn)(v8::StartupData*)) {
-  startup_data->data = NULL;
-  startup_data->raw_size = 0;
+void Load(const char* blob_file, v8::StartupData* startup_data,
+          void (*setter_fn)(v8::StartupData*)) {
+  ClearStartupData(startup_data);
 
   if (!blob_file) return;
 
@@ -86,6 +61,57 @@ void StartupDataHandler::Load(const char* blob_file,
   if (startup_data->raw_size == read_size) (*setter_fn)(startup_data);
 }
 
+
+void LoadFromFiles(const char* natives_blob, const char* snapshot_blob) {
+  Load(natives_blob, &g_natives, v8::V8::SetNativesDataBlob);
+  Load(snapshot_blob, &g_snapshot, v8::V8::SetSnapshotDataBlob);
+
+  atexit(&FreeStartupData);
+}
+
+
+char* RelativePath(char** buffer, const char* exec_path, const char* name) {
+  DCHECK(exec_path);
+  int path_separator = static_cast<int>(strlen(exec_path)) - 1;
+  while (path_separator >= 0 &&
+         !base::OS::isDirectorySeparator(exec_path[path_separator])) {
+    path_separator--;
+  }
+  if (path_separator >= 0) {
+    int name_length = static_cast<int>(strlen(name));
+    *buffer =
+        reinterpret_cast<char*>(calloc(path_separator + name_length + 2, 1));
+    *buffer[0] = '\0';
+    strncat(*buffer, exec_path, path_separator + 1);
+    strncat(*buffer, name, name_length);
+  } else {
+    *buffer = strdup(name);
+  }
+  return *buffer;
+}
+
+}  // namespace
 #endif  // V8_USE_EXTERNAL_STARTUP_DATA
 
+
+void InitializeExternalStartupData(const char* directory_path) {
+#ifdef V8_USE_EXTERNAL_STARTUP_DATA
+  char* natives;
+  char* snapshot;
+  LoadFromFiles(RelativePath(&natives, directory_path, "natives_blob.bin"),
+                RelativePath(&snapshot, directory_path, "snapshot_blob.bin"));
+  free(natives);
+  free(snapshot);
+#endif  // V8_USE_EXTERNAL_STARTUP_DATA
+}
+
+
+void InitializeExternalStartupData(const char* natives_blob,
+                                   const char* snapshot_blob) {
+#ifdef V8_USE_EXTERNAL_STARTUP_DATA
+  LoadFromFiles(natives_blob, snapshot_blob);
+#endif  // V8_USE_EXTERNAL_STARTUP_DATA
+}
+
+}  // namespace internal
 }  // namespace v8
diff --git a/deps/v8/src/startup-data-util.h b/deps/v8/src/startup-data-util.h
index 79b4171343a1b6..7cb51e362a9010 100644
--- a/deps/v8/src/startup-data-util.h
+++ b/deps/v8/src/startup-data-util.h
@@ -9,43 +9,21 @@
 #include "include/v8.h"
 
 namespace v8 {
+namespace internal {
 
-#ifdef V8_USE_EXTERNAL_STARTUP_DATA
-// Helper class to load the startup data files from disk.
+// Helper functions to load external startup data.
 //
 // This is meant as a convenience for stand-alone binaries like d8, cctest,
 // unittest. A V8 embedder would likely either handle startup data on their
 // own or just disable the feature if they don't want to handle it at all,
-// while tools like cctest need to work in either configuration. Hence this is
-// not meant for inclusion in the general v8 library.
-class StartupDataHandler {
- public:
-  // Load startup data, and call the v8::V8::Set*DataBlob API functions.
-  //
-  // natives_blob and snapshot_blob will be loaded realitive to exec_path,
-  // which would usually be the equivalent of argv[0].
-  StartupDataHandler(const char* exec_path, const char* natives_blob,
-                     const char* snapshot_blob);
-  ~StartupDataHandler();
-
- private:
-  static char* RelativePath(char** buffer, const char* exec_path,
-                            const char* name);
-
-  void LoadFromFiles(const char* natives_blob, const char* snapshot_blob);
-
-  void Load(const char* blob_file, v8::StartupData* startup_data,
-            void (*setter_fn)(v8::StartupData*));
-
-  v8::StartupData natives_;
-  v8::StartupData snapshot_;
-
-  // Disallow copy & assign.
-  StartupDataHandler(const StartupDataHandler& other);
-  void operator=(const StartupDataHandler& other);
-};
-#endif  // V8_USE_EXTERNAL_STARTUP_DATA
+// while tools like cctest need to work in either configuration.
 
+void InitializeExternalStartupData(const char* directory_path);
+
+void InitializeExternalStartupData(const char* natives_blob,
+                                   const char* snapshot_blob);
+
+}  // namespace internal
 }  // namespace v8
 
 #endif  // V8_STARTUP_DATA_UTIL_H_
diff --git a/deps/v8/test/cctest/cctest.cc b/deps/v8/test/cctest/cctest.cc
index b5771ff6550681..851096ddce27f2 100644
--- a/deps/v8/test/cctest/cctest.cc
+++ b/deps/v8/test/cctest/cctest.cc
@@ -34,10 +34,6 @@
 #include "test/cctest/profiler-extension.h"
 #include "test/cctest/trace-extension.h"
 
-#ifdef V8_USE_EXTERNAL_STARTUP_DATA
-#include "src/startup-data-util.h"
-#endif  // V8_USE_EXTERNAL_STARTUP_DATA
-
 #if V8_OS_WIN
 #include <windows.h>  // NOLINT
 #if V8_CC_MSVC
@@ -173,9 +169,7 @@ int main(int argc, char* argv[]) {
   v8::V8::InitializePlatform(platform);
   v8::internal::FlagList::SetFlagsFromCommandLine(&argc, argv, true);
   v8::V8::Initialize();
-#ifdef V8_USE_EXTERNAL_STARTUP_DATA
-  v8::StartupDataHandler startup_data(argv[0], NULL, NULL);
-#endif
+  v8::V8::InitializeExternalStartupData(argv[0]);
 
   CcTestArrayBufferAllocator array_buffer_allocator;
   CcTest::set_array_buffer_allocator(&array_buffer_allocator);
diff --git a/deps/v8/test/cctest/cctest.gyp b/deps/v8/test/cctest/cctest.gyp
index bcbbe7b226d576..8f0c58d38e7cf9 100644
--- a/deps/v8/test/cctest/cctest.gyp
+++ b/deps/v8/test/cctest/cctest.gyp
@@ -163,8 +163,6 @@
         'test-weakmaps.cc',
         'test-weaksets.cc',
         'trace-extension.cc',
-        '../../src/startup-data-util.h',
-        '../../src/startup-data-util.cc'
       ],
       'conditions': [
         ['v8_target_arch=="ia32"', {
diff --git a/deps/v8/test/cctest/test-parsing.cc b/deps/v8/test/cctest/test-parsing.cc
index cbb79b16da9cc7..cfb43911aa2b3d 100644
--- a/deps/v8/test/cctest/test-parsing.cc
+++ b/deps/v8/test/cctest/test-parsing.cc
@@ -3516,6 +3516,67 @@ TEST(UseConstLegacyCount) {
 }
 
 
+TEST(ErrorsArrowFormalParameters) {
+  const char* context_data[][2] = {
+    { "()", "=>{}" },
+    { "()", "=>{};" },
+    { "var x = ()", "=>{}" },
+    { "var x = ()", "=>{};" },
+
+    { "a", "=>{}" },
+    { "a", "=>{};" },
+    { "var x = a", "=>{}" },
+    { "var x = a", "=>{};" },
+
+    { "(a)", "=>{}" },
+    { "(a)", "=>{};" },
+    { "var x = (a)", "=>{}" },
+    { "var x = (a)", "=>{};" },
+
+    { "(...a)", "=>{}" },
+    { "(...a)", "=>{};" },
+    { "var x = (...a)", "=>{}" },
+    { "var x = (...a)", "=>{};" },
+
+    { "(a,b)", "=>{}" },
+    { "(a,b)", "=>{};" },
+    { "var x = (a,b)", "=>{}" },
+    { "var x = (a,b)", "=>{};" },
+
+    { "(a,...b)", "=>{}" },
+    { "(a,...b)", "=>{};" },
+    { "var x = (a,...b)", "=>{}" },
+    { "var x = (a,...b)", "=>{};" },
+
+    { nullptr, nullptr }
+  };
+  const char* assignment_expression_suffix_data[] = {
+    "?c:d=>{}",
+    "=c=>{}",
+    "()",
+    "(c)",
+    "[1]",
+    "[c]",
+    ".c",
+    "-c",
+    "+c",
+    "c++",
+    "`c`",
+    "`${c}`",
+    "`template-head${c}`",
+    "`${c}template-tail`",
+    "`template-head${c}template-tail`",
+    "`${c}template-tail`",
+    nullptr
+  };
+
+  static const ParserFlag always_flags[] = { kAllowHarmonyArrowFunctions,
+                                             kAllowHarmonyRestParameters };
+  RunParserSyncTest(context_data, assignment_expression_suffix_data, kError,
+                    NULL, 0, always_flags, arraysize(always_flags));
+}
+
+
 TEST(ErrorsArrowFunctions) {
   // Tests that parser and preparser generate the same kind of errors
   // on invalid arrow function syntax.
diff --git a/deps/v8/test/unittests/run-all-unittests.cc b/deps/v8/test/unittests/run-all-unittests.cc
index 08d265624bf84e..0b7f65e08e1939 100644
--- a/deps/v8/test/unittests/run-all-unittests.cc
+++ b/deps/v8/test/unittests/run-all-unittests.cc
@@ -7,10 +7,6 @@
 #include "src/base/compiler-specific.h"
 #include "testing/gmock/include/gmock/gmock.h"
 
-#ifdef V8_USE_EXTERNAL_STARTUP_DATA
-#include "src/startup-data-util.h"
-#endif  // V8_USE_EXTERNAL_STARTUP_DATA
-
 namespace {
 
 class DefaultPlatformEnvironment final : public ::testing::Environment {
@@ -45,8 +41,6 @@ int main(int argc, char** argv) {
   testing::InitGoogleMock(&argc, argv);
   testing::AddGlobalTestEnvironment(new DefaultPlatformEnvironment);
   v8::V8::SetFlagsFromCommandLine(&argc, argv, true);
-#ifdef V8_USE_EXTERNAL_STARTUP_DATA
-  v8::StartupDataHandler startup_data(argv[0], NULL, NULL);
-#endif
+  v8::V8::InitializeExternalStartupData(argv[0]);
   return RUN_ALL_TESTS();
 }
diff --git a/deps/v8/test/unittests/unittests.gyp b/deps/v8/test/unittests/unittests.gyp
index 00658b3fda2df9..9698fb760dbb11 100644
--- a/deps/v8/test/unittests/unittests.gyp
+++ b/deps/v8/test/unittests/unittests.gyp
@@ -94,8 +94,6 @@
         'run-all-unittests.cc',
         'test-utils.h',
         'test-utils.cc',
-        '../../src/startup-data-util.h',
-        '../../src/startup-data-util.cc'
       ],
       'conditions': [
         ['v8_target_arch=="arm"', {
diff --git a/deps/v8/tools/gyp/v8.gyp b/deps/v8/tools/gyp/v8.gyp
index a77acfa1091ed9..400991c43fc14e 100644
--- a/deps/v8/tools/gyp/v8.gyp
+++ b/deps/v8/tools/gyp/v8.gyp
@@ -910,6 +910,8 @@
         '../../src/snapshot/snapshot-source-sink.h',
         '../../src/splay-tree.h',
         '../../src/splay-tree-inl.h',
+        '../../src/startup-data-util.cc',
+        '../../src/startup-data-util.h',
         '../../src/string-builder.cc',
         '../../src/string-builder.h',
         '../../src/string-search.cc',
diff --git a/deps/v8/tools/parser-shell.cc b/deps/v8/tools/parser-shell.cc
index ead7777022fd52..da874595de4bb1 100644
--- a/deps/v8/tools/parser-shell.cc
+++ b/deps/v8/tools/parser-shell.cc
@@ -146,6 +146,8 @@ int main(int argc, char* argv[]) {
   v8::Platform* platform = v8::platform::CreateDefaultPlatform();
   v8::V8::InitializePlatform(platform);
   v8::V8::Initialize();
+  v8::V8::InitializeExternalStartupData(argv[0]);
+
   Encoding encoding = LATIN1;
   std::vector<std::string> fnames;
   std::string benchmark;