Revert of cc: Add image decode queue functionality to image manager.

cc/tiles/software_image_decode_cache.h

Index: cc/tiles/software_image_decode_cache.h
diff --git a/cc/tiles/software_image_decode_cache.h b/cc/tiles/software_image_decode_cache.h
index 1f3d72f27d83511d657d5c8d4220e364c996b2c4..9befb55dad464ba69139e7343a021cc20d29804c 100644
--- a/cc/tiles/software_image_decode_cache.h
+++ b/cc/tiles/software_image_decode_cache.h
@@ -109,8 +109,6 @@
   using ImageKey = ImageDecodeCacheKey;
   using ImageKeyHash = ImageDecodeCacheKeyHash;
 
-  enum class DecodeTaskType { USE_IN_RASTER_TASKS, USE_OUT_OF_RASTER_TASKS };
-
   SoftwareImageDecodeCache(ResourceFormat format,
                            size_t locked_memory_limit_bytes);
   ~SoftwareImageDecodeCache() override;
@@ -119,9 +117,6 @@
   bool GetTaskForImageAndRef(const DrawImage& image,
                              const TracingInfo& tracing_info,
                              scoped_refptr<TileTask>* task) override;
-  bool GetOutOfRasterDecodeTaskForImageAndRef(
-      const DrawImage& image,
-      scoped_refptr<TileTask>* task) override;
   void UnrefImage(const DrawImage& image) override;
   DecodedDrawImage GetDecodedImageForDraw(const DrawImage& image) override;
   void DrawWithImageFinished(const DrawImage& image,
@@ -133,11 +128,9 @@
 
   // Decode the given image and store it in the cache. This is only called by an
   // image decode task from a worker thread.
-  void DecodeImage(const ImageKey& key,
-                   const DrawImage& image,
-                   DecodeTaskType task_type);
-
-  void RemovePendingTask(const ImageKey& key, DecodeTaskType task_type);
+  void DecodeImage(const ImageKey& key, const DrawImage& image);
+
+  void RemovePendingTask(const ImageKey& key);
 
   // MemoryDumpProvider overrides.
   bool OnMemoryDump(const base::trace_event::MemoryDumpArgs& args,
@@ -274,17 +267,8 @@
   // Overriden from base::MemoryCoordinatorClient.
   void OnMemoryStateChange(base::MemoryState state) override;
 
-  // Helper method to get the different tasks. Note that this should be used as
-  // if it was public (ie, all of the locks need to be properly acquired).
-  bool GetTaskForImageAndRefInternal(const DrawImage& image,
-                                     const TracingInfo& tracing_info,
-                                     DecodeTaskType type,
-                                     scoped_refptr<TileTask>* task);
-
   std::unordered_map<ImageKey, scoped_refptr<TileTask>, ImageKeyHash>
-      pending_in_raster_image_tasks_;
-  std::unordered_map<ImageKey, scoped_refptr<TileTask>, ImageKeyHash>
-      pending_out_of_raster_image_tasks_;
+      pending_image_tasks_;
 
   // The members below this comment can only be accessed if the lock is held to
   // ensure that they are safe to access on multiple threads.