cc: Add checker-imaging support to TileManager.

cc/playback/image_hijack_canvas.h

 // Copyright 2016 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_PLAYBACK_IMAGE_HIJACK_CANVAS_H_
 #define CC_PLAYBACK_IMAGE_HIJACK_CANVAS_H_
 
+#include <unordered_set>
+
 #include "base/macros.h"
 #include "cc/base/cc_export.h"
+#include "cc/playback/image_id.h"
 #include "third_party/skia/include/utils/SkNWayCanvas.h"
 
 namespace cc {
 
 class ImageDecodeCache;
 
 class CC_EXPORT ImageHijackCanvas : public SkNWayCanvas {
  public:
   ImageHijackCanvas(int width,
                     int height,
-                    ImageDecodeCache* image_decode_cache);
+                    ImageDecodeCache* image_decode_cache,
+                    const std::unordered_set<ImageId>* images_to_skip);

[vmpstr, 2017/02/10 19:25:42]

maybe use base::flat_set here? Or vector? I feel like whenever we use an
unordered set, we kind of want justification for why that's better over vector

Realistically, this will be empty for a lot of cases and very small when it's
not empty.

[Khushal, 2017/02/10 22:09:19]

Done. So other cases where we have sets are in CheckerImageTracker. I think the
images_decoded_once_ should definitely remain a set. Do you have an opinion
about the rest there?

 
  private:
   // Ensure that pictures are unpacked by this canvas, instead of being
   // forwarded to the raster canvas.
   void onDrawPicture(const SkPicture* picture,
                      const SkMatrix* matrix,
                      const SkPaint* paint) override;
   void onDrawImage(const SkImage* image,
                    SkScalar x,
                    SkScalar y,
@@ skipping 10 matching lines @@
                  SkScalar start_angle,
                  SkScalar sweep_angle,
                  bool use_center,
                  const SkPaint& paint) override;
   void onDrawRRect(const SkRRect& rr, const SkPaint& paint) override;
   void onDrawImageNine(const SkImage* image,
                        const SkIRect& center,
                        const SkRect& dst,
                        const SkPaint* paint) override;
 
+  bool ShouldSkipImage(const SkImage* image);
+
   ImageDecodeCache* image_decode_cache_;
+  const std::unordered_set<ImageId>* images_to_skip_;
 
   DISALLOW_COPY_AND_ASSIGN(ImageHijackCanvas);
 };
 
 }  // namespace cc
 
 #endif  // CC_PLAYBACK_IMAGE_HIJACK_CANVAS_H_