Started ignoring remote keyboard notifications. (flutter#17981)

shell/platform/darwin/ios/framework/Source/FlutterViewController.mm

@@ -33,62 +33,6 @@
 NSNotificationName const FlutterViewControllerShowHomeIndicator =
     @"FlutterViewControllerShowHomeIndicator";
 
-/// Class to coalesce calls for a period of time.
-///
-/// This is used to filter out the conflicting notifications that can get sent
-/// in rapid succession when the app gets foregrounded.
-@interface FlutterCoalescer : NSObject
-@property(nonatomic, assign) BOOL isTriggered;
-@property(nonatomic, assign) BOOL isCoalescing;
-@property(nonatomic, copy) dispatch_block_t block;
-@end
-
-@implementation FlutterCoalescer
-- (instancetype)initWithBlock:(dispatch_block_t)block {
-  self = [super init];
-  if (self) {
-    self.block = block;
-  }
-  return self;
-}
-
-- (void)dealloc {
-  [_block release];
-  [super dealloc];
-}
-
-- (void)trigger {
-  if (_isCoalescing) {
-    _isTriggered = YES;
-  } else {
-    _isTriggered = NO;
-    if (_block) {
-      _block();
-    }
-  }
-}
-
-- (void)coalesceForSeconds:(double)seconds {
-  if (self.isCoalescing || !self.block) {
-    return;
-  }
-  self.isCoalescing = YES;
-  dispatch_after(dispatch_time(DISPATCH_TIME_NOW, seconds * NSEC_PER_SEC),
-                 dispatch_get_main_queue(), ^{
-                   if (self.isTriggered && self.block) {
-                     self.block();
-                   }
-                   self.isTriggered = NO;
-                   self.isCoalescing = NO;
-                 });
-}
-
-- (void)invalidate {
-  self.block = nil;
-}
-
-@end  // FlutterCoalescer
-
 // This is left a FlutterBinaryMessenger privately for now to give people a chance to notice the
 // change. Unfortunately unless you have Werror turned on, incompatible pointers as arguments are
 // just a warning.
@@ -127,9 +71,6 @@ @implementation FlutterViewController {
   BOOL _viewOpaque;
   BOOL _engineNeedsLaunch;
   NSMutableSet<NSNumber*>* _ongoingTouches;
-  // Coalescer that filters out superfluous keyboard notifications when the app
-  // is being foregrounded.
-  fml::scoped_nsobject<FlutterCoalescer> _updateViewportMetrics;
   // This scroll view is a workaround to accomodate iOS 13 and higher.  There isn't a way to get
   // touches on the status bar to trigger scrolling to the top of a scroll view.  We place a
   // UIScrollView with height zero and a content offset so we can get those events. See also:
@@ -226,11 +167,6 @@ - (void)performCommonViewControllerInitialization {
   _statusBarStyle = UIStatusBarStyleDefault;
 
   [self setupNotificationCenterObservers];
-
-  __block FlutterViewController* blockSelf = self;
-  _updateViewportMetrics.reset([[FlutterCoalescer alloc] initWithBlock:^{
-    [blockSelf updateViewportMetricsImplementation];
-  }]);
 }
 
 - (FlutterEngine*)engine {
@@ -668,7 +604,6 @@ - (void)dealloc {
                                                     userInfo:nil];
   [[NSNotificationCenter defaultCenter] removeObserver:self];
   [_ongoingTouches release];
-  [_updateViewportMetrics invalidate];
   [super dealloc];
 }
 
@@ -695,7 +630,6 @@ - (void)applicationDidEnterBackground:(NSNotification*)notification {
 - (void)applicationWillEnterForeground:(NSNotification*)notification {
   TRACE_EVENT0("flutter", "applicationWillEnterForeground");
   [self goToApplicationLifecycle:@"AppLifecycleState.inactive"];
-  [_updateViewportMetrics coalesceForSeconds:0.5];
 }
 
 // Make this transition only while this current view controller is visible.
@@ -886,13 +820,6 @@ - (void)touchesCancelled:(NSSet*)touches withEvent:(UIEvent*)event {
 #pragma mark - Handle view resizing
 
 - (void)updateViewportMetrics {
-  [_updateViewportMetrics trigger];
-}
-
-/// The direct implementation of updateViewportMetrics, it doesn't conform to
-/// the coalescing logic when foregrounding the app.  Most calls should be
-/// directed to [updateViewportMetrics].
-- (void)updateViewportMetricsImplementation {
   [_engine.get() updateViewportMetrics:_viewportMetrics];
 }
 
@@ -920,7 +847,7 @@ - (void)viewDidLayoutSubviews {
   _viewportMetrics.physical_height = viewSize.height * scale;
 
   [self updateViewportPadding];
-  [self updateViewportMetricsImplementation];
+  [self updateViewportMetrics];
 
   // This must run after updateViewportMetrics so that the surface creation tasks are queued after
   // the viewport metrics update tasks.
@@ -967,6 +894,15 @@ - (void)updateViewportPadding {
 
 - (void)keyboardWillChangeFrame:(NSNotification*)notification {
   NSDictionary* info = [notification userInfo];
+
+  if (@available(iOS 9, *)) {
+    // Ignore keyboard notifications related to other apps.
+    id isLocal = info[UIKeyboardIsLocalUserInfoKey];
+    if (isLocal && ![isLocal boolValue]) {
+      return;
+    }
+  }
+
   CGRect keyboardFrame = [[info objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];
   CGRect screenRect = [[UIScreen mainScreen] bounds];