cc: Add image decode queue functionality to image manager.

cc/tiles/gpu_image_decode_cache_unittest.cc

 // 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.
 
 #include "cc/tiles/gpu_image_decode_cache.h"
 
 #include "cc/playback/draw_image.h"
 #include "cc/test/test_context_provider.h"
 #include "cc/test/test_tile_task_runner.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ skipping 479 matching lines @@
   sk_sp<SkImage> image = CreateImage(100, 100);
   DrawImage draw_image(image, SkIRect::MakeWH(image->width(), image->height()),
                        quality,
                        CreateMatrix(SkSize::Make(0.5f, 0.5f), is_decomposable));
   scoped_refptr<TileTask> task;
   bool need_unref = cache.GetTaskForImageAndRef(
       draw_image, ImageDecodeCache::TracingInfo(), &task);
   EXPECT_TRUE(need_unref);
   EXPECT_TRUE(task);
 
+  ASSERT_GT(task->dependencies().size(), 0u);
   TestTileTaskRunner::ProcessTask(task->dependencies()[0].get());
 
   scoped_refptr<TileTask> another_task;
   need_unref = cache.GetTaskForImageAndRef(
       draw_image, ImageDecodeCache::TracingInfo(), &another_task);
   EXPECT_TRUE(need_unref);
   EXPECT_TRUE(another_task.get() == task.get());
 
   // Didn't run the task, so cancel it.
   TestTileTaskRunner::CancelTask(task.get());
   TestTileTaskRunner::CompleteTask(task.get());
 
+  // 2 Unrefs, so that the decode is unlocked as well.
+  cache.UnrefImage(draw_image);
+  cache.UnrefImage(draw_image);
+
   // Note that here, everything is reffed, but a new task is created. This is
   // possible with repeated schedule/cancel operations.
   scoped_refptr<TileTask> third_task;
   need_unref = cache.GetTaskForImageAndRef(
       draw_image, ImageDecodeCache::TracingInfo(), &third_task);
   EXPECT_TRUE(need_unref);
   EXPECT_TRUE(third_task);
   EXPECT_FALSE(third_task.get() == task.get());
 
+  ASSERT_GT(third_task->dependencies().size(), 0u);
   TestTileTaskRunner::ProcessTask(third_task->dependencies()[0].get());
   TestTileTaskRunner::ProcessTask(third_task.get());
 
-  // 3 Unrefs!
-  cache.UnrefImage(draw_image);
-  cache.UnrefImage(draw_image);
+  // Unref!
   cache.UnrefImage(draw_image);
 }
 
 TEST(GpuImageDecodeCacheTest, NoTaskForImageAlreadyFailedDecoding) {
   auto context_provider = TestContextProvider::Create();
   context_provider->BindToCurrentThread();
   TestGpuImageDecodeCache cache(context_provider.get());
   bool is_decomposable = true;
   SkFilterQuality quality = kHigh_SkFilterQuality;
 
@@ skipping 819 matching lines @@
   EXPECT_TRUE(need_unref);
   EXPECT_TRUE(task);
 
   TestTileTaskRunner::ProcessTask(task->dependencies()[0].get());
   TestTileTaskRunner::ProcessTask(task.get());
   cache.UnrefImage(draw_image);
 }
 
 }  // namespace
 }  // namespace cc