cc: Add image decode queue functionality to image manager.

cc/tiles/image_controller.h

Index: cc/tiles/image_controller.h
diff --git a/cc/tiles/image_controller.h b/cc/tiles/image_controller.h
index 983aa14985839aae402449c051b1c9f7fdb8be23..3f0bf75875646385255b15391493593be9b5bde5 100644
--- a/cc/tiles/image_controller.h
+++ b/cc/tiles/image_controller.h
@@ -5,11 +5,15 @@
 #ifndef CC_TILES_IMAGE_CONTROLLER_H_
 #define CC_TILES_IMAGE_CONTROLLER_H_
 
+#include <set>
 #include <vector>
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
+#include "base/threading/simple_thread.h"
 #include "cc/base/cc_export.h"
+#include "cc/base/unique_notifier.h"
 #include "cc/playback/draw_image.h"
 #include "cc/raster/tile_task.h"
 #include "cc/tiles/image_decode_cache.h"
@@ -18,7 +22,9 @@ namespace cc {
 
 class CC_EXPORT ImageController {
  public:
-  ImageController();
+  using ImageDecodeRequestId = uint64_t;
+  using ImageDecodedCallback = base::Callback<void(ImageDecodeRequestId)>;
+  explicit ImageController(base::SequencedTaskRunner* task_runner);
   ~ImageController();
 
   void SetImageDecodeCache(ImageDecodeCache* cache);
@@ -32,13 +38,61 @@ class CC_EXPORT ImageController {
       std::vector<DrawImage> predecode_images,
       const ImageDecodeCache::TracingInfo& tracing_info);
 
+  ImageDecodeRequestId QueueImageDecode(sk_sp<const SkImage> image,
+                                        const ImageDecodedCallback& callback);
+  void NotifyFrameFinished();
+
+  // Called from the worker thread.
+  void ProcessImageDecodes();
+
  private:
+  struct ImageDecodeRequest {
+    ImageDecodeRequest();
+    ImageDecodeRequest(ImageDecodeRequestId id,
+                       const DrawImage& draw_image,
+                       const ImageDecodedCallback& callback,
+                       scoped_refptr<TileTask> task,
+                       bool need_unref);
+    ImageDecodeRequest(ImageDecodeRequest&& other);
+    ImageDecodeRequest(const ImageDecodeRequest& other);
+    ~ImageDecodeRequest();
+
+    ImageDecodeRequest& operator=(ImageDecodeRequest&& other);
+    ImageDecodeRequest& operator=(const ImageDecodeRequest& other);
+
+    ImageDecodeRequestId id;
+    DrawImage draw_image;
+    ImageDecodedCallback callback;
+    scoped_refptr<TileTask> task;
+    bool need_unref;
+  };
+
+  void StartWorkerThread();
+  void StopWorkerThread();
+
+  void ImageDecodeCompleted(ImageDecodeRequestId id);
+
   ImageDecodeCache* cache_ = nullptr;
   std::vector<DrawImage> predecode_locked_images_;
 
   // Debugging information for crbug.com/650234.
   size_t num_times_cache_was_set_ = 0;
 
+  static ImageDecodeRequestId s_next_image_decode_queue_id_;
+  std::map<ImageDecodeRequestId, ImageDecodeRequest> image_decode_queue_;
+  std::map<ImageDecodeRequestId, ImageDecodeRequest>
+      requests_needing_completion_;
+  std::vector<std::pair<DrawImage, int>> requested_locked_images_;
+
+  base::SequencedTaskRunner* task_runner_ = nullptr;
+  base::Lock lock_;
+  base::ConditionVariable work_available_cv_;
+  std::unique_ptr<base::SimpleThread> worker_thread_;
+
+  bool shutdown_ = true;
+
+  base::WeakPtrFactory<ImageController> weak_ptr_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(ImageController);
 };