Correct handling for alwaysUse24HourFormat in MediaQuery (#13287)

1. Ensure that this value is defaulted to the value associated with the
   context rather than re-defaulted to false.
2. Add this value to operator==, hashCode, toString methods.

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

@@ -117,6 +117,7 @@ class MediaQueryData {
     double textScaleFactor,
     EdgeInsets padding,
     EdgeInsets viewInsets,
+    bool alwaysUse24HourFormat,
   }) {
     return new MediaQueryData(
       size: size ?? this.size,
@@ -124,6 +125,7 @@ class MediaQueryData {
       textScaleFactor: textScaleFactor ?? this.textScaleFactor,
       padding: padding ?? this.padding,
       viewInsets: viewInsets ?? this.viewInsets,
+      alwaysUse24HourFormat: alwaysUse24HourFormat ?? this.alwaysUse24HourFormat,
     );
   }
 
@@ -159,6 +161,7 @@ class MediaQueryData {
         bottom: removeBottom ? 0.0 : null,
       ),
       viewInsets: viewInsets,
+      alwaysUse24HourFormat: alwaysUse24HourFormat,
     );
   }
 
@@ -171,16 +174,18 @@ class MediaQueryData {
         && typedOther.devicePixelRatio == devicePixelRatio
         && typedOther.textScaleFactor == textScaleFactor
         && typedOther.padding == padding
-        && typedOther.viewInsets == viewInsets;
+        && typedOther.viewInsets == viewInsets
+        && typedOther.alwaysUse24HourFormat == alwaysUse24HourFormat;
   }
 
   @override
-  int get hashCode => hashValues(size, devicePixelRatio, textScaleFactor, padding, viewInsets);
+  int get hashCode => hashValues(size, devicePixelRatio, textScaleFactor, padding, viewInsets, alwaysUse24HourFormat);
 
   @override
   String toString() {
     return '$runtimeType(size: $size, devicePixelRatio: $devicePixelRatio, '
-           'textScaleFactor: $textScaleFactor, padding: $padding, viewInsets: $viewInsets)';
+           'textScaleFactor: $textScaleFactor, padding: $padding, '
+           'viewInsets: $viewInsets, alwaysUse24HourFormat: $alwaysUse24HourFormat)';
   }
 }
 

packages/flutter/test/widgets/media_query_test.dart

@@ -53,6 +53,7 @@ void main() {
     expect(copied.textScaleFactor, data.textScaleFactor);
     expect(copied.padding, data.padding);
     expect(copied.viewInsets, data.viewInsets);
+    expect(copied.alwaysUse24HourFormat, data.alwaysUse24HourFormat);
   });
 
   testWidgets('MediaQuery.copyWith copies specified values', (WidgetTester tester) async {
@@ -63,30 +64,22 @@ void main() {
       textScaleFactor: 1.62,
       padding: const EdgeInsets.all(9.10938),
       viewInsets: const EdgeInsets.all(1.67262),
+      alwaysUse24HourFormat: true,
     );
     expect(copied.size, const Size(3.14, 2.72));
     expect(copied.devicePixelRatio, 1.41);
     expect(copied.textScaleFactor, 1.62);
     expect(copied.padding, const EdgeInsets.all(9.10938));
     expect(copied.viewInsets, const EdgeInsets.all(1.67262));
+    expect(copied.alwaysUse24HourFormat, true);
   });
 
   testWidgets('MediaQuery.removePadding removes specified padding', (WidgetTester tester) async {
     const Size size = const Size(2.0, 4.0);
     const double devicePixelRatio = 2.0;
     const double textScaleFactor = 1.2;
-    const EdgeInsets padding = const EdgeInsets.only(
-      top: 1.0,
-      right: 2.0,
-      left: 3.0,
-      bottom: 4.0,
-    );
-    const EdgeInsets viewInsets = const EdgeInsets.only(
-      top: 5.0,
-      right: 6.0,
-      left: 7.0,
-      bottom: 8.0,
-    );
+    const EdgeInsets padding = const EdgeInsets.only(top: 1.0, right: 2.0, left: 3.0, bottom: 4.0);
+    const EdgeInsets viewInsets = const EdgeInsets.only(top: 5.0, right: 6.0, left: 7.0, bottom: 8.0);
 
     MediaQueryData unpadded;
     await tester.pumpWidget(
@@ -97,6 +90,7 @@ void main() {
           textScaleFactor: textScaleFactor,
           padding: padding,
           viewInsets: viewInsets,
+          alwaysUse24HourFormat: true,
         ),
         child: new Builder(
           builder: (BuildContext context) {
@@ -122,5 +116,6 @@ void main() {
     expect(unpadded.textScaleFactor, textScaleFactor);
     expect(unpadded.padding, EdgeInsets.zero);
     expect(unpadded.viewInsets, viewInsets);
+    expect(unpadded.alwaysUse24HourFormat, true);
   });
 }