SetNeedsRedraw directly when updating a visible tile.

cc/test/fake_picture_pile.h

Index: cc/test/fake_picture_pile.h
diff --git a/cc/test/fake_picture_pile.h b/cc/test/fake_picture_pile.h
index e486e3b4cd37c63fb53bc38c13f6c9ababb83622..10b899ec9460ecc06e53a296237158dc08004d4a 100644
--- a/cc/test/fake_picture_pile.h
+++ b/cc/test/fake_picture_pile.h
@@ -8,11 +8,16 @@
 #include "cc/resources/picture_pile.h"
 
 namespace cc {
+class ThreadBlocker;
 
 class FakePicturePile : public PicturePile {
  public:
+  FakePicturePile() : raster_thread_blocker_(nullptr) {}
   ~FakePicturePile() override {}
 
+  // PicturePile overrides.
+  scoped_refptr<RasterSource> CreateRasterSource() const override;
+
   using PicturePile::buffer_pixels;
   using PicturePile::CanRasterSlowTileCheck;
   using PicturePile::Clear;
@@ -37,6 +42,10 @@ class FakePicturePile : public PicturePile {
     has_any_recordings_ = has_recordings;
   }
 
+  void SetRasterThreadBlocker(ThreadBlocker* blocker) {
+    raster_thread_blocker_ = blocker;
+  }
+
   TilingData& tiling() { return tiling_; }
 
   bool is_solid_color() const { return is_solid_color_; }
@@ -47,7 +56,11 @@ class FakePicturePile : public PicturePile {
   typedef PicturePile::PictureInfo PictureInfo;
   typedef PicturePile::PictureMapKey PictureMapKey;
   typedef PicturePile::PictureMap PictureMap;
+
+ private:
+  ThreadBlocker* raster_thread_blocker_;
 };
+
 }  // namespace cc
 
 #endif  // CC_TEST_FAKE_PICTURE_PILE_H_