Move binarySearch implementation in animated_list to foundation/collection.dart. (#29860)

packages/flutter/lib/src/foundation/collections.dart

@@ -45,3 +45,26 @@ bool listEquals<T>(List<T> a, List<T> b) {
   }
   return true;
 }
+
+/// Returns the position of `value` in the `sortedList`, if it exists.
+///
+/// Returns `-1` if the `value` is not in the list. Requires the list items
+/// to implement [Comparable] and the `sortedList` to already be ordered.
+int binarySearch<T extends Comparable<Object>>(List<T> sortedList, T value) {
+  int min = 0;
+  int max = sortedList.length;
+  while (min < max) {
+    final int mid = min + ((max - min) >> 1);
+    final T element = sortedList[mid];
+    final int comp = element.compareTo(value);
+    if (comp == 0) {
+      return mid;
+    }
+    if (comp < 0) {
+      min = mid + 1;
+    } else {
+      max = mid;
+    }
+  }
+  return -1;
+}

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

@@ -74,13 +74,17 @@ class _TaskEntry<T> {
   Completer<T> completer;
 
   void run() {
-    Timeline.timeSync(
-      debugLabel ?? 'Scheduled Task',
-      () {
-        completer.complete(task());
-      },
-      flow: flow != null ? Flow.step(flow.id) : null,
-    );
+    if (!kReleaseMode) {
+      Timeline.timeSync(
+        debugLabel ?? 'Scheduled Task',
+        () {
+          completer.complete(task());
+        },
+        flow: flow != null ? Flow.step(flow.id) : null,
+      );
+    } else {
+      completer.complete(task());
+    }
   }
 }
 

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

@@ -2,9 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'package:collection/collection.dart' show binarySearch;
-
 import 'package:flutter/animation.dart';
+import 'package:flutter/foundation.dart';
 
 import 'basic.dart';
 import 'framework.dart';

packages/flutter/test/foundation/binary_search_test.dart

+// Copyright 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter/src/foundation/collections.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  test('binarySearch', () {
+    final List<int> items = <int>[1, 2, 3];
+
+    expect(binarySearch(items, 1), 0);
+    expect(binarySearch(items, 2), 1);
+    expect(binarySearch(items, 3), 2);
+    expect(binarySearch(items, 12), -1);
+  });
+}