diff --git a/fml/platform/win/wstring_conversion.cc b/fml/platform/win/wstring_conversion.cc
index ef87f60e89e6b..6e4e36e8cf629 100644
--- a/fml/platform/win/wstring_conversion.cc
+++ b/fml/platform/win/wstring_conversion.cc
@@ -23,16 +23,4 @@ std::wstring Utf8ToWideString(const std::string_view str) {
   return converter.from_bytes(str.data());
 }
 
-std::u16string WideStringToUtf16(const std::wstring_view str) {
-  static_assert(sizeof(std::wstring::value_type) ==
-                sizeof(std::u16string::value_type));
-  return {begin(str), end(str)};
-}
-
-std::wstring Utf16ToWideString(const std::u16string_view str) {
-  static_assert(sizeof(std::wstring::value_type) ==
-                sizeof(std::u16string::value_type));
-  return {begin(str), end(str)};
-}
-
 }  // namespace fml
diff --git a/fml/platform/win/wstring_conversion.h b/fml/platform/win/wstring_conversion.h
index cc5dbb680ae60..4e7c110685491 100644
--- a/fml/platform/win/wstring_conversion.h
+++ b/fml/platform/win/wstring_conversion.h
@@ -16,12 +16,6 @@ std::string WideStringToUtf8(const std::wstring_view str);
 // string.
 std::wstring Utf8ToWideString(const std::string_view str);
 
-// Returns a UTF-16 encoded equivalent of a UTF-16 encoded wide string.
-std::u16string WideStringToUtf16(const std::wstring_view str);
-
-// Returns a UTF-16 encoded wide string equivalent of a UTF-16 string.
-std::wstring Utf16ToWideString(const std::u16string_view str);
-
 }  // namespace fml
 
 #endif  // FLUTTER_FML_PLATFORM_WIN_WSTRING_CONVERSION_H_
diff --git a/fml/platform/win/wstring_conversion_unittests.cc b/fml/platform/win/wstring_conversion_unittests.cc
index 1f726720fc511..81af2594ce94c 100644
--- a/fml/platform/win/wstring_conversion_unittests.cc
+++ b/fml/platform/win/wstring_conversion_unittests.cc
@@ -9,7 +9,7 @@
 namespace fml {
 namespace testing {
 
-TEST(StringConversion, Utf8ToWideStringEmpty) {
+TEST(StringConversion, Utf16ToWideStringEmpty) {
   EXPECT_EQ(Utf8ToWideString(""), L"");
 }
 
@@ -33,29 +33,5 @@ TEST(StringConversion, WideStringToUtf8Unicode) {
   EXPECT_EQ(WideStringToUtf8(L"\x2603"), "\xe2\x98\x83");
 }
 
-TEST(StringConversion, WideStringToUtf16Empty) {
-  EXPECT_EQ(WideStringToUtf16(L""), u"");
-}
-
-TEST(StringConversion, WideStringToUtf16Ascii) {
-  EXPECT_EQ(WideStringToUtf16(L"abc123"), u"abc123");
-}
-
-TEST(StringConversion, WideStringToUtf16Unicode) {
-  EXPECT_EQ(WideStringToUtf16(L"\xe2\x98\x83"), u"\xe2\x98\x83");
-}
-
-TEST(StringConversion, Utf16ToWideStringEmpty) {
-  EXPECT_EQ(Utf16ToWideString(u""), L"");
-}
-
-TEST(StringConversion, Utf16ToWideStringAscii) {
-  EXPECT_EQ(Utf16ToWideString(u"abc123"), L"abc123");
-}
-
-TEST(StringConversion, Utf16ToWideStringUtf8Unicode) {
-  EXPECT_EQ(Utf16ToWideString(u"\xe2\x98\x83"), L"\xe2\x98\x83");
-}
-
 }  // namespace testing
 }  // namespace fml
diff --git a/third_party/accessibility/ax/BUILD.gn b/third_party/accessibility/ax/BUILD.gn
index fc07993a3fe70..d03e3cde122de 100644
--- a/third_party/accessibility/ax/BUILD.gn
+++ b/third_party/accessibility/ax/BUILD.gn
@@ -106,7 +106,6 @@ source_set("ax") {
       "oleacc.lib",
       "uiautomationcore.lib",
     ]
-    deps = [ "//flutter/fml:string_conversion" ]
   }
 
   public_deps = [
diff --git a/third_party/accessibility/ax/ax_node_position_unittest.cc b/third_party/accessibility/ax/ax_node_position_unittest.cc
index b5b993d4723a6..18677f3697eae 100644
--- a/third_party/accessibility/ax/ax_node_position_unittest.cc
+++ b/third_party/accessibility/ax/ax_node_position_unittest.cc
@@ -19,7 +19,6 @@
 #include "ax/ax_tree_id.h"
 #include "ax/ax_tree_update.h"
 #include "ax/test_ax_tree_manager.h"
-#include "flutter/fml/platform/win/wstring_conversion.h"
 #include "gtest/gtest.h"
 
 namespace ui {
@@ -29,6 +28,10 @@ using TestPositionRange = AXRange<AXPosition<AXNodePosition, AXNode>>;
 
 namespace {
 
+std::u16string WideToUTF16(const std::wstring wide) {
+  return std::u16string(wide.begin(), wide.end());
+}
+
 constexpr AXNode::AXID ROOT_ID = 1;
 constexpr AXNode::AXID BUTTON_ID = 2;
 constexpr AXNode::AXID CHECK_BOX_ID = 3;
@@ -40,20 +43,20 @@ constexpr AXNode::AXID STATIC_TEXT2_ID = 8;
 constexpr AXNode::AXID INLINE_BOX2_ID = 9;
 
 // A group of basic and extended characters.
-constexpr const char16_t* kGraphemeClusters[] = {
+constexpr const wchar_t* kGraphemeClusters[] = {
     // The English word "hey" consisting of four ASCII characters.
-    u"h",
-    u"e",
-    u"y",
+    L"h",
+    L"e",
+    L"y",
     // A Hindi word (which means "Hindi") consisting of two Devanagari
     // grapheme clusters.
-    u"\x0939\x093F",
-    u"\x0928\x094D\x0926\x0940",
+    L"\x0939\x093F",
+    L"\x0928\x094D\x0926\x0940",
     // A Thai word (which means "feel") consisting of three Thai grapheme
     // clusters.
-    u"\x0E23\x0E39\x0E49",
-    u"\x0E2A\x0E36",
-    u"\x0E01",
+    L"\x0E23\x0E39\x0E49",
+    L"\x0E2A\x0E36",
+    L"\x0E01",
 };
 
 class AXPositionTest : public testing::Test, public TestAXTreeManager {
@@ -416,7 +419,7 @@ std::unique_ptr<AXTree> AXPositionTest::CreateMultilingualDocument(
 
   std::u16string english_text;
   for (int i = 0; i < 3; ++i) {
-    std::u16string grapheme = kGraphemeClusters[i];
+    std::u16string grapheme = WideToUTF16(kGraphemeClusters[i]);
     EXPECT_EQ(1u, grapheme.length())
         << "All English characters should be one UTF16 code unit in length.";
     text_offsets->push_back(text_offsets->back() +
@@ -426,7 +429,7 @@ std::unique_ptr<AXTree> AXPositionTest::CreateMultilingualDocument(
 
   std::u16string hindi_text;
   for (int i = 3; i < 5; ++i) {
-    std::u16string grapheme = kGraphemeClusters[i];
+    std::u16string grapheme = WideToUTF16(kGraphemeClusters[i]);
     EXPECT_LE(2u, grapheme.length()) << "All Hindi characters should be two "
                                         "or more UTF16 code units in length.";
     text_offsets->push_back(text_offsets->back() +
@@ -436,7 +439,7 @@ std::unique_ptr<AXTree> AXPositionTest::CreateMultilingualDocument(
 
   std::u16string thai_text;
   for (int i = 5; i < 8; ++i) {
-    std::u16string grapheme = kGraphemeClusters[i];
+    std::u16string grapheme = WideToUTF16(kGraphemeClusters[i]);
     EXPECT_LT(0u, grapheme.length())
         << "One of the Thai characters should be one UTF16 code unit, "
            "whilst others should be two or more.";
@@ -615,7 +618,7 @@ TEST_F(AXPositionTest, ToString) {
   AXNodeData static_text_data_2;
   static_text_data_2.id = 3;
   static_text_data_2.role = ax::mojom::Role::kStaticText;
-  static_text_data_2.SetName(u"\xfffc");
+  static_text_data_2.SetName(WideToUTF16(L"\xfffc"));
 
   AXNodeData static_text_data_3;
   static_text_data_3.id = 4;
@@ -873,7 +876,7 @@ TEST_F(AXPositionTest, GetTextFromNullPosition) {
   TestPositionType text_position = AXNodePosition::CreateNullPosition();
   ASSERT_NE(nullptr, text_position);
   ASSERT_TRUE(text_position->IsNullPosition());
-  ASSERT_EQ(u"", text_position->GetText());
+  ASSERT_EQ(WideToUTF16(L""), text_position->GetText());
 }
 
 TEST_F(AXPositionTest, GetTextFromRoot) {
@@ -882,7 +885,7 @@ TEST_F(AXPositionTest, GetTextFromRoot) {
       ax::mojom::TextAffinity::kUpstream);
   ASSERT_NE(nullptr, text_position);
   ASSERT_TRUE(text_position->IsTextPosition());
-  ASSERT_EQ(u"Line 1\nLine 2", text_position->GetText());
+  ASSERT_EQ(WideToUTF16(L"Line 1\nLine 2"), text_position->GetText());
 }
 
 TEST_F(AXPositionTest, GetTextFromButton) {
@@ -891,7 +894,7 @@ TEST_F(AXPositionTest, GetTextFromButton) {
       ax::mojom::TextAffinity::kUpstream);
   ASSERT_NE(nullptr, text_position);
   ASSERT_TRUE(text_position->IsTextPosition());
-  ASSERT_EQ(u"", text_position->GetText());
+  ASSERT_EQ(WideToUTF16(L""), text_position->GetText());
 }
 
 TEST_F(AXPositionTest, GetTextFromCheckbox) {
@@ -900,7 +903,7 @@ TEST_F(AXPositionTest, GetTextFromCheckbox) {
       ax::mojom::TextAffinity::kUpstream);
   ASSERT_NE(nullptr, text_position);
   ASSERT_TRUE(text_position->IsTextPosition());
-  ASSERT_EQ(u"", text_position->GetText());
+  ASSERT_EQ(WideToUTF16(L""), text_position->GetText());
 }
 
 TEST_F(AXPositionTest, GetTextFromTextField) {
@@ -909,7 +912,7 @@ TEST_F(AXPositionTest, GetTextFromTextField) {
       ax::mojom::TextAffinity::kUpstream);
   ASSERT_NE(nullptr, text_position);
   ASSERT_TRUE(text_position->IsTextPosition());
-  ASSERT_EQ(u"Line 1\nLine 2", text_position->GetText());
+  ASSERT_EQ(WideToUTF16(L"Line 1\nLine 2"), text_position->GetText());
 }
 
 TEST_F(AXPositionTest, GetTextFromStaticText) {
@@ -918,7 +921,7 @@ TEST_F(AXPositionTest, GetTextFromStaticText) {
       ax::mojom::TextAffinity::kUpstream);
   ASSERT_NE(nullptr, text_position);
   ASSERT_TRUE(text_position->IsTextPosition());
-  ASSERT_EQ(u"Line 1", text_position->GetText());
+  ASSERT_EQ(WideToUTF16(L"Line 1"), text_position->GetText());
 }
 
 TEST_F(AXPositionTest, GetTextFromInlineTextBox) {
@@ -927,7 +930,7 @@ TEST_F(AXPositionTest, GetTextFromInlineTextBox) {
       ax::mojom::TextAffinity::kUpstream);
   ASSERT_NE(nullptr, text_position);
   ASSERT_TRUE(text_position->IsTextPosition());
-  ASSERT_EQ(u"Line 1", text_position->GetText());
+  ASSERT_EQ(WideToUTF16(L"Line 1"), text_position->GetText());
 }
 
 TEST_F(AXPositionTest, GetTextFromLineBreak) {
@@ -936,7 +939,7 @@ TEST_F(AXPositionTest, GetTextFromLineBreak) {
       ax::mojom::TextAffinity::kUpstream);
   ASSERT_NE(nullptr, text_position);
   ASSERT_TRUE(text_position->IsTextPosition());
-  ASSERT_EQ(u"\n", text_position->GetText());
+  ASSERT_EQ(WideToUTF16(L"\n"), text_position->GetText());
 }
 
 TEST_F(AXPositionTest, GetMaxTextOffsetFromNullPosition) {
@@ -1103,7 +1106,7 @@ TEST_F(AXPositionTest, GetMaxTextOffsetAndGetTextWithGeneratedContent) {
   ASSERT_NE(nullptr, text_position);
   EXPECT_TRUE(text_position->IsTextPosition());
   EXPECT_EQ(38, text_position->MaxTextOffset());
-  EXPECT_EQ(u"Placeholder from generated content3.14",
+  EXPECT_EQ(WideToUTF16(L"Placeholder from generated content3.14"),
             text_position->GetText());
 }
 
@@ -7709,10 +7712,10 @@ TEST_F(AXPositionTest, EmptyObjectReplacedByCharacterTextNavigation) {
       GetTreeID(), root_1.id, 0 /* text_offset */,
       ax::mojom::TextAffinity::kDownstream);
 
-  expected_text =
-      std::u16string(u"Hello ") + AXNodePosition::kEmbeddedCharacter +
-      std::u16string(u" world3.14") + AXNodePosition::kEmbeddedCharacter +
-      std::u16string(u"hey") + AXNodePosition::kEmbeddedCharacter;
+  expected_text = WideToUTF16(L"Hello ") + AXNodePosition::kEmbeddedCharacter +
+                  WideToUTF16(L" world3.14") +
+                  AXNodePosition::kEmbeddedCharacter + WideToUTF16(L"hey") +
+                  AXNodePosition::kEmbeddedCharacter;
   ASSERT_EQ(expected_text, position->GetText());
 
   // MaxTextOffset() with an embedded object replacement character.
diff --git a/third_party/accessibility/ax/platform/ax_platform_node_textprovider_win_unittest.cc b/third_party/accessibility/ax/platform/ax_platform_node_textprovider_win_unittest.cc
index b3d1c98a15e04..2b3a846da46e9 100644
--- a/third_party/accessibility/ax/platform/ax_platform_node_textprovider_win_unittest.cc
+++ b/third_party/accessibility/ax/platform/ax_platform_node_textprovider_win_unittest.cc
@@ -349,7 +349,7 @@ TEST_F(AXPlatformNodeTextProviderTest,
   base::win::ScopedBstr text_content;
   EXPECT_HRESULT_SUCCEEDED(
       text_range_provider->GetText(-1, text_content.Receive()));
-  EXPECT_EQ(fml::WideStringToUtf16(text_content.Get()),
+  EXPECT_EQ(base::WideToUTF16(text_content.Get()),
             u"Dialog label.Dialog description." + kEmbeddedCharacterAsString +
                 u"ok.Some more detail " + u"about dialog.");
 
diff --git a/third_party/accessibility/ax/platform/ax_platform_node_textrangeprovider_win.cc b/third_party/accessibility/ax/platform/ax_platform_node_textrangeprovider_win.cc
index 71f72d3395085..2c7cca0e2e81b 100644
--- a/third_party/accessibility/ax/platform/ax_platform_node_textrangeprovider_win.cc
+++ b/third_party/accessibility/ax/platform/ax_platform_node_textrangeprovider_win.cc
@@ -13,7 +13,6 @@
 #include "ax/platform/ax_platform_node_win.h"
 #include "ax/platform/ax_platform_tree_manager.h"
 #include "base/win/variant_vector.h"
-#include "flutter/fml/platform/win/wstring_conversion.h"
 
 #define UIA_VALIDATE_TEXTRANGEPROVIDER_CALL()                  \
   if (!GetOwner() || !GetOwner()->GetDelegate() || !start() || \
@@ -484,7 +483,7 @@ HRESULT AXPlatformNodeTextRangeProviderWin::FindText(
   ScopedAXEmbeddedObjectBehaviorSetter ax_embedded_object_behavior(
       AXEmbeddedObjectBehavior::kSuppressCharacter);
 
-  std::u16string search_string = fml::WideStringToUtf16(string);
+  std::u16string search_string = base::WideToUTF16(string);
   if (search_string.length() <= 0)
     return E_INVALIDARG;
 
@@ -704,7 +703,7 @@ HRESULT AXPlatformNodeTextRangeProviderWin::GetText(int max_count, BSTR* text) {
   if (max_count < -1)
     return E_INVALIDARG;
 
-  std::wstring full_text = fml::Utf16ToWideString(GetString(max_count));
+  std::wstring full_text = base::UTF16ToWide(GetString(max_count));
   if (!full_text.empty()) {
     size_t length = full_text.length();
 
diff --git a/third_party/accessibility/ax/platform/ax_platform_node_win.cc b/third_party/accessibility/ax/platform/ax_platform_node_win.cc
index fcc7b8b3b6486..b00f5d2c58eaf 100644
--- a/third_party/accessibility/ax/platform/ax_platform_node_win.cc
+++ b/third_party/accessibility/ax/platform/ax_platform_node_win.cc
@@ -38,7 +38,6 @@
 #include "base/logging.h"
 #include "base/win/atl_module.h"
 #include "base/win/display.h"
-#include "flutter/fml/platform/win/wstring_conversion.h"
 #include "gfx/geometry/rect_conversions.h"
 
 // From ax.constants.mojom
@@ -964,7 +963,7 @@ IFACEMETHODIMP AXPlatformNodeWin::get_accDefaultAction(VARIANT var_id,
     return S_FALSE;
   }
 
-  *def_action = ::SysAllocString(fml::Utf16ToWideString(action_verb).c_str());
+  *def_action = ::SysAllocString(base::UTF16ToWide(action_verb).c_str());
   BASE_DCHECK(def_action);
   return S_OK;
 }
@@ -1055,7 +1054,7 @@ IFACEMETHODIMP AXPlatformNodeWin::get_accName(VARIANT var_id, BSTR* name_bstr) {
   if (name.empty() && !has_name)
     return S_FALSE;
 
-  *name_bstr = ::SysAllocString(fml::Utf16ToWideString(name).c_str());
+  *name_bstr = ::SysAllocString(base::UTF16ToWide(name).c_str());
   return S_OK;
 }
 
@@ -1750,7 +1749,7 @@ IFACEMETHODIMP AXPlatformNodeWin::SetValue(LPCWSTR value) {
 
   AXActionData data;
   data.action = ax::mojom::Action::kSetValue;
-  data.value = base::UTF16ToUTF8(fml::WideStringToUtf16(value));
+  data.value = base::UTF16ToUTF8(base::WideToUTF16(value));
   if (GetDelegate()->AccessibilityPerformAction(data))
     return S_OK;
   return E_FAIL;
@@ -2133,20 +2132,20 @@ HRESULT AXPlatformNodeWin::GetPropertyValueImpl(PROPERTYID property_id,
   switch (property_id) {
     case UIA_AriaPropertiesPropertyId:
       result->vt = VT_BSTR;
-      result->bstrVal = ::SysAllocString(
-          fml::Utf16ToWideString(ComputeUIAProperties()).c_str());
+      result->bstrVal =
+          ::SysAllocString(base::UTF16ToWide(ComputeUIAProperties()).c_str());
       break;
 
     case UIA_AriaRolePropertyId:
       result->vt = VT_BSTR;
       result->bstrVal =
-          ::SysAllocString(fml::Utf16ToWideString(UIAAriaRole()).c_str());
+          ::SysAllocString(base::UTF16ToWide(UIAAriaRole()).c_str());
       break;
 
     case UIA_AutomationIdPropertyId:
       V_VT(result) = VT_BSTR;
       V_BSTR(result) = ::SysAllocString(
-          fml::Utf16ToWideString(GetDelegate()->GetAuthorUniqueId()).c_str());
+          base::UTF16ToWide(GetDelegate()->GetAuthorUniqueId()).c_str());
       break;
 
     case UIA_ClassNamePropertyId:
@@ -2315,8 +2314,8 @@ HRESULT AXPlatformNodeWin::GetPropertyValueImpl(PROPERTYID property_id,
       std::u16string localized_control_type = GetRoleDescription();
       if (!localized_control_type.empty()) {
         result->vt = VT_BSTR;
-        result->bstrVal = ::SysAllocString(
-            fml::Utf16ToWideString(localized_control_type).c_str());
+        result->bstrVal =
+            ::SysAllocString(base::UTF16ToWide(localized_control_type).c_str());
       }
       // If a role description has not been provided, leave as VT_EMPTY.
       // UIA core handles Localized Control type for some built-in types and
@@ -2467,7 +2466,7 @@ HRESULT AXPlatformNodeWin::GetPropertyValueImpl(PROPERTYID property_id,
       if (!localized_landmark_type.empty()) {
         result->vt = VT_BSTR;
         result->bstrVal = ::SysAllocString(
-            fml::Utf16ToWideString(localized_landmark_type).c_str());
+            base::UTF16ToWide(localized_landmark_type).c_str());
       }
       break;
     }
@@ -2526,7 +2525,7 @@ HRESULT AXPlatformNodeWin::GetPropertyValueImpl(PROPERTYID property_id,
     // convention here and when we fire events via ::NotifyWinEvent().
     result->vt = VT_BSTR;
     result->bstrVal = ::SysAllocString(
-        fml::Utf16ToWideString(base::NumberToString16(-GetUniqueId())).c_str());
+        base::UTF16ToWide(base::NumberToString16(-GetUniqueId())).c_str());
   }
 
   return S_OK;
@@ -5315,7 +5314,7 @@ BSTR AXPlatformNodeWin::GetValueAttributeAsBstr(AXPlatformNodeWin* target) {
     value_text = base::NumberToString16(red * 100 / 255) + u"% red " +
                  base::NumberToString16(green * 100 / 255) + u"% green " +
                  base::NumberToString16(blue * 100 / 255) + u"% blue";
-    BSTR value = ::SysAllocString(fml::Utf16ToWideString(value_text).c_str());
+    BSTR value = ::SysAllocString(base::UTF16ToWide(value_text).c_str());
     BASE_DCHECK(value);
     return value;
   }
@@ -5326,7 +5325,7 @@ BSTR AXPlatformNodeWin::GetValueAttributeAsBstr(AXPlatformNodeWin* target) {
   if (target->GetData().role == ax::mojom::Role::kRootWebArea ||
       target->GetData().role == ax::mojom::Role::kWebArea) {
     result = base::UTF8ToUTF16(target->GetDelegate()->GetTreeData().url);
-    BSTR value = ::SysAllocString(fml::Utf16ToWideString(result).c_str());
+    BSTR value = ::SysAllocString(base::UTF16ToWide(result).c_str());
     BASE_DCHECK(value);
     return value;
   }
@@ -5336,7 +5335,7 @@ BSTR AXPlatformNodeWin::GetValueAttributeAsBstr(AXPlatformNodeWin* target) {
   //
   if (target->GetData().role == ax::mojom::Role::kLink) {
     result = target->GetString16Attribute(ax::mojom::StringAttribute::kUrl);
-    BSTR value = ::SysAllocString(fml::Utf16ToWideString(result).c_str());
+    BSTR value = ::SysAllocString(base::UTF16ToWide(result).c_str());
     BASE_DCHECK(value);
     return value;
   }
@@ -5351,7 +5350,7 @@ BSTR AXPlatformNodeWin::GetValueAttributeAsBstr(AXPlatformNodeWin* target) {
     if (target->GetFloatAttribute(ax::mojom::FloatAttribute::kValueForRange,
                                   &fval)) {
       result = base::NumberToString16(fval);
-      BSTR value = ::SysAllocString(fml::Utf16ToWideString(result).c_str());
+      BSTR value = ::SysAllocString(base::UTF16ToWide(result).c_str());
       BASE_DCHECK(value);
       return value;
     }
@@ -5360,7 +5359,7 @@ BSTR AXPlatformNodeWin::GetValueAttributeAsBstr(AXPlatformNodeWin* target) {
   if (result.empty() && target->IsRichTextField())
     result = target->GetInnerText();
 
-  BSTR value = ::SysAllocString(fml::Utf16ToWideString(result).c_str());
+  BSTR value = ::SysAllocString(base::UTF16ToWide(result).c_str());
   BASE_DCHECK(value);
   return value;
 }
@@ -5373,7 +5372,7 @@ HRESULT AXPlatformNodeWin::GetStringAttributeAsBstr(
   if (!GetString16Attribute(attribute, &str))
     return S_FALSE;
 
-  *value_bstr = ::SysAllocString(fml::Utf16ToWideString(str).c_str());
+  *value_bstr = ::SysAllocString(base::UTF16ToWide(str).c_str());
   BASE_DCHECK(*value_bstr);
 
   return S_OK;
@@ -5381,7 +5380,7 @@ HRESULT AXPlatformNodeWin::GetStringAttributeAsBstr(
 
 HRESULT AXPlatformNodeWin::GetNameAsBstr(BSTR* value_bstr) const {
   std::u16string str = GetNameAsString16();
-  *value_bstr = ::SysAllocString(fml::Utf16ToWideString(str).c_str());
+  *value_bstr = ::SysAllocString(base::UTF16ToWide(str).c_str());
   BASE_DCHECK(*value_bstr);
   return S_OK;
 }
@@ -5491,14 +5490,14 @@ BSTR AXPlatformNodeWin::GetFontNameAttributeAsBSTR() const {
   const std::u16string string =
       GetInheritedString16Attribute(ax::mojom::StringAttribute::kFontFamily);
 
-  return ::SysAllocString(fml::Utf16ToWideString(string).c_str());
+  return ::SysAllocString(base::UTF16ToWide(string).c_str());
 }
 
 BSTR AXPlatformNodeWin::GetStyleNameAttributeAsBSTR() const {
   std::u16string style_name =
       GetDelegate()->GetStyleNameAttributeAsLocalizedString();
 
-  return ::SysAllocString(fml::Utf16ToWideString(style_name).c_str());
+  return ::SysAllocString(base::UTF16ToWide(style_name).c_str());
 }
 
 TextDecorationLineStyle AXPlatformNodeWin::GetUIATextDecorationStyle(
diff --git a/third_party/accessibility/base/string_utils.cc b/third_party/accessibility/base/string_utils.cc
index 963f7d581d4f7..61e0a4a257f4a 100644
--- a/third_party/accessibility/base/string_utils.cc
+++ b/third_party/accessibility/base/string_utils.cc
@@ -72,6 +72,14 @@ std::string UTF16ToUTF8(std::u16string src) {
   return fml::Utf16ToUtf8(src);
 }
 
+std::u16string WideToUTF16(const std::wstring& src) {
+  return std::u16string(src.begin(), src.end());
+}
+
+std::wstring UTF16ToWide(const std::u16string& src) {
+  return std::wstring(src.begin(), src.end());
+}
+
 std::u16string NumberToString16(float number) {
   return ASCIIToUTF16(NumberToString(number));
 }
diff --git a/third_party/accessibility/base/string_utils.h b/third_party/accessibility/base/string_utils.h
index ceddfbf2b0b15..6e3c6c6153ce9 100644
--- a/third_party/accessibility/base/string_utils.h
+++ b/third_party/accessibility/base/string_utils.h
@@ -26,6 +26,8 @@ std::string StringPrintf(const std::string& format, Args... args) {
 std::u16string ASCIIToUTF16(std::string src);
 std::u16string UTF8ToUTF16(std::string src);
 std::string UTF16ToUTF8(std::u16string src);
+std::u16string WideToUTF16(const std::wstring& src);
+std::wstring UTF16ToWide(const std::u16string& src);
 
 std::u16string NumberToString16(unsigned int number);
 std::u16string NumberToString16(int32_t number);