SetNeedsRedraw directly when updating a visible tile.

cc/test/fake_picture_pile.h

+// 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.
+
+#ifndef CC_TEST_FAKE_PICTURE_PILE_H_
+#define CC_TEST_FAKE_PICTURE_PILE_H_
+
+#include "cc/resources/picture_pile.h"
+
+namespace cc {
+class ThreadBlocker;
+
+class FakePicturePile : public PicturePile {
+ public:
+  explicit FakePicturePile(ThreadBlocker* blocker)
+      : raster_thread_blocker_(blocker) {}
+  virtual ~FakePicturePile() {}
+
+  // PicturePile overrides.
+  scoped_refptr<RasterSource> CreateRasterSource() const override;
+
+ private:
+  ThreadBlocker* raster_thread_blocker_;
+};
+
+}  // namespace cc
+
+#endif  // CC_TEST_FAKE_PICTURE_PILE_H_