cc: Move (partially) the predecode image tracking to ImageManager.

cc/tiles/image_manager.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/image_manager.h"
 
 namespace cc {
 
 ImageManager::ImageManager() = default;
 ImageManager::~ImageManager() = default;
 
 void ImageManager::SetImageDecodeController(ImageDecodeController* controller) {
+  if (!controller_) {
+    SetPredecodeImages(std::vector<DrawImage>(),

[enne (OOO), 2016/09/16 17:45:44]

Why do you need to do this? Why would there be locked images before an image
controller is set? (Or why wouldn't you do this when the image decode controller
changed vs is set for the first time?)

Do you mean controller and not controller_?

[vmpstr, 2016/09/16 18:11:49]

Errr, yeah I meant controller here. I've added a test for this.

+                       ImageDecodeController::TracingInfo());
+  }
   controller_ = controller;
 }
 
 void ImageManager::GetTasksForImagesAndRef(
     std::vector<DrawImage>* images,
     std::vector<scoped_refptr<TileTask>>* tasks,
     const ImageDecodeController::TracingInfo& tracing_info) {
   DCHECK(controller_);
   for (auto it = images->begin(); it != images->end();) {
     scoped_refptr<TileTask> task;
@@ skipping 13 matching lines @@
   DCHECK(controller_);
   for (auto image : images)
     controller_->UnrefImage(image);
 }
 
 void ImageManager::ReduceMemoryUsage() {
   DCHECK(controller_);
   controller_->ReduceCacheUsage();
 }
 
+std::vector<scoped_refptr<TileTask>> ImageManager::SetPredecodeImages(
+    std::vector<DrawImage> images,
+    const ImageDecodeController::TracingInfo& tracing_info) {
+  std::vector<scoped_refptr<TileTask>> new_tasks;
+  GetTasksForImagesAndRef(&images, &new_tasks, tracing_info);
+  UnrefImages(predecode_locked_images_);
+  predecode_locked_images_ = std::move(images);
+  return new_tasks;
+}
+
 }  // namespace cc