Improve comment spelling consistency (#6622)

packages/flutter/lib/painting.dart

@@ -7,7 +7,7 @@
 /// To use, import `package:flutter/painting.dart`.
 ///
 /// This library includes a variety of classes that wrap the Flutter
-/// engine's painting API for more specialised purposes, such as painting scaled
+/// engine's painting API for more specialized purposes, such as painting scaled
 /// images, interpolating between shadows, painting borders around boxes, etc.
 ///
 /// In particular:

packages/flutter/lib/src/gestures/constants.dart

@@ -11,7 +11,7 @@ const Duration kPressTimeout = const Duration(milliseconds: 100);
 
 /// Maximum length of time between a tap down and a tap up for the gesture to be
 /// considered a tap. (Currently not honored by the TapGestureRecognizer.)
-// TODO(ianh): Remove this, or implement a hover-tap gesture recogniser which
+// TODO(ianh): Remove this, or implement a hover-tap gesture recognizer which
 // uses this.
 const Duration kHoverTapTimeout = const Duration(milliseconds: 150);
 

packages/flutter/lib/src/gestures/recognizer.dart

@@ -43,7 +43,7 @@ abstract class GestureRecognizer extends GestureArenaMember {
   ///
   /// This method is called by the owner of this gesture recognizer
   /// when the object is no longer needed (e.g. when a gesture
-  /// recogniser is being unregistered from a [GestureDetector], the
+  /// recognizer is being unregistered from a [GestureDetector], the
   /// GestureDetector widget calls this method).
   @mustCallSuper
   void dispose() { }
@@ -178,7 +178,7 @@ enum GestureRecognizerState {
   /// been accepted definitively.
   possible,
 
-  /// Further pointer events cannot cause this recognizer to recognise the
+  /// Further pointer events cannot cause this recognizer to recognize the
   /// gesture until the recognizer returns to the [ready] state (typically when
   /// all the pointers the recognizer is tracking are removed from the screen).
   defunct,

packages/flutter/lib/src/material/ink_well.dart

@@ -15,7 +15,7 @@ import 'theme.dart';
 /// An area of a [Material] that responds to touch. Has a configurable shape and
 /// can be configured to clip splashes that extend outside its bounds or not.
 ///
-/// For a variant of this widget that is specialised for rectangular areas that
+/// For a variant of this widget that is specialized for rectangular areas that
 /// always clip splashes, see [InkWell].
 ///
 /// Must have an ancestor [Material] widget in which to cause ink reactions.

packages/flutter/lib/src/physics/friction_simulation.dart

@@ -72,7 +72,7 @@ class FrictionSimulation extends Simulation {
   bool isDone(double time) => dx(time).abs() < tolerance.velocity;
 }
 
-/// A [FrictionSimulation] that clamps the modelled particle to a specific range
+/// A [FrictionSimulation] that clamps the modeled particle to a specific range
 /// of values.
 class BoundedFrictionSimulation extends FrictionSimulation {
   /// Creates a [BoundedFrictionSimulation] with the given arguments, namely:

packages/flutter/lib/src/rendering/box.dart

@@ -339,7 +339,7 @@ class BoxConstraints extends Constraints {
   }
 
   /// Returns whether the object's constraints are normalized.
-  /// Constraints are normalised if the minimums are less than or
+  /// Constraints are normalized if the minimums are less than or
   /// equal to the corresponding maximums.
   ///
   /// For example, a BoxConstraints object with a minWidth of 100.0

packages/flutter/lib/src/scheduler/binding.dart

@@ -128,7 +128,7 @@ enum SchedulerPhase {
 /// Scheduler for running the following:
 ///
 /// * _Frame callbacks_, triggered by the system's
-///   [ui.window.onBeginFrame] callback, for synchronising the
+///   [ui.window.onBeginFrame] callback, for synchronizing the
 ///   application's behavior to the system's display. For example, the
 ///   rendering layer uses this to drive its rendering pipeline.
 ///

packages/flutter/lib/src/widgets/framework.dart

@@ -789,7 +789,7 @@ abstract class State<T extends StatefulWidget> {
   /// bundle may have changed).
   ///
   /// In addition to this method being invoked, it is guaranteed that the
-  /// [build] method will be invoked when a reassemble is signalled. Most
+  /// [build] method will be invoked when a reassemble is signaled. Most
   /// widgets therefore do not need to do anything in the [reassemble] method.
   ///
   /// This function will only be called during development. In release builds,
@@ -3281,7 +3281,7 @@ abstract class RenderObjectElement extends BuildableElement {
     // the old child list (old.children), and update our renderObject
     // accordingly.
 
-    // The cases it tries to optimise for are:
+    // The cases it tries to optimize for are:
     //  - the old list is empty
     //  - the lists are identical
     //  - there is an insertion or removal of one or more widgets in

packages/flutter/lib/src/widgets/gesture_detector.dart

@@ -388,8 +388,8 @@ class RawGestureDetectorState extends State<RawGestureDetector> {
         throw new FlutterError(
           'Unexpected call to replaceGestureRecognizers() method of RawGestureDetectorState.\n'
           'The replaceGestureRecognizers() method can only be called during the layout phase. '
-          'To set the gesture recognisers at other times, trigger a new build using setState() '
-          'and provide the new gesture recognisers as constructor arguments to the corresponding '
+          'To set the gesture recognizers at other times, trigger a new build using setState() '
+          'and provide the new gesture recognizers as constructor arguments to the corresponding '
           'RawGestureDetector or GestureDetector object.'
         );
       }