[blink] Fix crashes in CanvasRenderingContext2DTests.

third_party/WebKit/Source/modules/canvas2d/CanvasRenderingContext2DTest.cpp

 // Copyright 2014 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.
 
 #include "modules/canvas2d/CanvasRenderingContext2D.h"
 
 #include <memory>
 #include "bindings/core/v8/V8Binding.h"
 #include "bindings/core/v8/V8BindingForTesting.h"
 #include "core/dom/Document.h"
@@ skipping 1385 matching lines @@
 void OverrideScriptEnabled(Settings& settings) {
   // Simulate that we allow scripts, so that HTMLCanvasElement uses
   // LayoutHTMLCanvas.
   settings.SetScriptEnabled(true);
 }
 
 class CanvasRenderingContext2DTestWithTestingPlatform
     : public CanvasRenderingContext2DTest {
  protected:
   void SetUp() override {
+    platform_ = WTF::MakeUnique<ScopedTestingPlatformSupport<
+        TestingPlatformSupportWithMockScheduler>>();
     override_settings_function_ = &OverrideScriptEnabled;
-    platform_->AdvanceClockSeconds(1.);  // For non-zero DocumentParserTimings.
+    (*platform_)
+        ->AdvanceClockSeconds(1.);  // For non-zero DocumentParserTimings.
     CanvasRenderingContext2DTest::SetUp();
     GetDocument().View()->UpdateLayout();
   }
 
-  void RunUntilIdle() { platform_->RunUntilIdle(); }
+  void TearDown() override {
+    platform_.reset();
+    CanvasRenderingContext2DTest::TearDown();
+  }
 
-  ScopedTestingPlatformSupport<TestingPlatformSupportWithMockScheduler>
+  void RunUntilIdle() { (*platform_)->RunUntilIdle(); }
+
+  std::unique_ptr<
+      ScopedTestingPlatformSupport<TestingPlatformSupportWithMockScheduler>>
       platform_;
 };
 
 // https://crbug.com/708445: When the Canvas2DLayerBridge hibernates or wakes up
 // from hibernation, the compositing reasons for the canvas element may change.
 // In these cases, the element should request a compositing update.
 TEST_F(CanvasRenderingContext2DTestWithTestingPlatform,
        ElementRequestsCompositingUpdateOnHibernateAndWakeUp) {
   CreateContext(kNonOpaque);
   FakeGLES2Interface gl;
@@ skipping 25 matching lines @@
             layer->NeedsCompositingInputsUpdate());
 
   GetDocument().View()->UpdateAllLifecyclePhases();
   EXPECT_FALSE(layer->NeedsCompositingInputsUpdate());
 
   // Wake up again, which should request a compositing update synchronously.
   GetDocument().GetPage()->SetVisibilityState(kPageVisibilityStateVisible,
                                               false);
   EXPECT_EQ(!!CANVAS2D_HIBERNATION_ENABLED,
             layer->NeedsCompositingInputsUpdate());
+  RunUntilIdle();  // Clear task queue.
 }
 
 }  // namespace blink