cc: Disallow img.decode images from being checker imaged.

cc/tiles/checker_image_tracker.h

Index: cc/tiles/checker_image_tracker.h
diff --git a/cc/tiles/checker_image_tracker.h b/cc/tiles/checker_image_tracker.h
index 9f64d8d3f06232b30e79f7f2ce2ec6084a7720ee..dcfa73fadcb89be91eeddacf4524e9c383cca90b 100644
--- a/cc/tiles/checker_image_tracker.h
+++ b/cc/tiles/checker_image_tracker.h
@@ -58,6 +58,11 @@ class CC_EXPORT CheckerImageTracker {
   // in re-checkering any images already decoded by the tracker.
   void ClearTracker(bool can_clear_decode_policy_tracking);
 
+  // Informs the tracker to not checker the given image. This can be used to opt
+  // out of the checkering behavior for certain images, such as ones that were
+  // decoded using the img.decode api.
+  void DisallowCheckeringForImage(const PaintImage& image);
+
  private:
   enum class DecodePolicy {
     // The image can be decoded asynchronously from raster. When set, the image
@@ -123,6 +128,8 @@ class CC_EXPORT CheckerImageTracker {
       image_id_to_decode_;
 
   base::WeakPtrFactory<CheckerImageTracker> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(CheckerImageTracker);
 };
 
 }  // namespace cc