cc: Add image decode control in the compositor.

cc/playback/display_list_raster_source.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_PLAYBACK_DISPLAY_LIST_RASTER_SOURCE_H_
 #define CC_PLAYBACK_DISPLAY_LIST_RASTER_SOURCE_H_
 
 #include <vector>
 
 #include "base/memory/scoped_ptr.h"
 #include "cc/base/cc_export.h"
 #include "cc/debug/rendering_stats_instrumentation.h"
 #include "cc/playback/display_list_recording_source.h"
 #include "skia/ext/analysis_canvas.h"
 #include "skia/ext/refptr.h"
 #include "third_party/skia/include/core/SkPicture.h"
 
 namespace cc {
 class DisplayItemList;
 class DrawImage;
+class ImageDecodeController;
 
 class CC_EXPORT DisplayListRasterSource
     : public base::RefCountedThreadSafe<DisplayListRasterSource> {
  public:
   struct CC_EXPORT SolidColorAnalysis {
     SolidColorAnalysis()
         : is_solid_color(false), solid_color(SK_ColorTRANSPARENT) {}
     ~SolidColorAnalysis() {}
 
     bool is_solid_color;
@@ skipping 68 matching lines @@
   virtual void DidBeginTracing();
   virtual void AsValueInto(base::trace_event::TracedValue* array) const;
   virtual skia::RefPtr<SkPicture> GetFlattenedPicture();
   virtual size_t GetPictureMemoryUsage() const;
 
   // Return true if LCD anti-aliasing may be used when rastering text.
   virtual bool CanUseLCDText() const;
 
   scoped_refptr<DisplayListRasterSource> CreateCloneWithoutLCDText() const;
 
+  // Image decode controller should be set once. Its lifetime has to exceed that
+  // of the raster source, since the raster source will access it during raster.
+  void SetImageDecodeController(ImageDecodeController* image_decode_controller);
+
  protected:
   friend class base::RefCountedThreadSafe<DisplayListRasterSource>;
 
   DisplayListRasterSource(const DisplayListRecordingSource* other,
                           bool can_use_lcd_text);
   DisplayListRasterSource(const DisplayListRasterSource* other,
                           bool can_use_lcd_text);
   virtual ~DisplayListRasterSource();
 
   // These members are const as this raster source may be in use on another
   // thread and so should not be touched after construction.
   const scoped_refptr<DisplayItemList> display_list_;
   const size_t painter_reported_memory_usage_;
   const SkColor background_color_;
   const bool requires_clear_;
   const bool can_use_lcd_text_;
   const bool is_solid_color_;
   const SkColor solid_color_;
   const gfx::Rect recorded_viewport_;
   const gfx::Size size_;
   const bool clear_canvas_with_debug_color_;
   const int slow_down_raster_scale_factor_for_debug_;
   // TODO(enne/vmiura): this has a read/write race between raster and compositor
   // threads with multi-threaded Ganesh.  Make this const or remove it.
   bool should_attempt_to_use_distance_field_text_;
 
+  ImageDecodeController* image_decode_controller_;

[ericrk, 2015/12/04 00:50:46]

Given all the warnings above re threading, can you add a comment here indicating
why this is threadsafe (I'm assuming it is only set once before any threaded
work begins?)

+
  private:
   // Called when analyzing a tile. We can use AnalysisCanvas as
   // SkPicture::AbortCallback, which allows us to early out from analysis.
   void RasterForAnalysis(skia::AnalysisCanvas* canvas,
                          const gfx::Rect& canvas_rect,
                          float contents_scale) const;
 
   void RasterCommon(SkCanvas* canvas,
                     SkPicture::AbortCallback* callback,
                     const gfx::Rect& canvas_bitmap_rect,
                     const gfx::Rect& canvas_playback_rect,
                     float contents_scale) const;
 
   void PrepareForPlaybackToCanvas(SkCanvas* canvas,
                                   const gfx::Rect& canvas_bitmap_rect,
                                   const gfx::Rect& canvas_playback_rect,
                                   float contents_scale) const;
 
   DISALLOW_COPY_AND_ASSIGN(DisplayListRasterSource);
 };
 
 }  // namespace cc
 
 #endif  // CC_PLAYBACK_DISPLAY_LIST_RASTER_SOURCE_H_