cc: Make image controller return a status with the callback.

cc/tiles/checker_image_tracker.cc

 // Copyright 2017 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/checker_image_tracker.h"
 
 #include "base/bind.h"
 #include "base/trace_event/trace_event.h"
 
 namespace cc {
@@ skipping 59 matching lines @@
     auto it = image_id_to_decode_request_id_.find(image_id);
     image_controller_->UnlockImageDecode(it->second);
     image_id_to_decode_request_id_.erase(it);
   }
 
   invalidated_images_on_current_sync_tree_.clear();
 }
 
 void CheckerImageTracker::DidFinishImageDecode(
     ImageId image_id,
-    ImageController::ImageDecodeRequestId request_id) {
+    ImageController::ImageDecodeRequestId request_id,
+    ImageController::ImageDecodeResult result) {

[Khushal, 2017/02/25 00:21:40]

May be DCHECK here that we never get decode not required, because in that case
we never should have queued a decode.

[vmpstr, 2017/02/27 21:25:28]

Done.

   TRACE_EVENT_ASYNC_END0("cc", "CheckerImageTracker::DeferImageDecode",
                          image_id);
 
   DCHECK_NE(pending_image_decodes_.count(image_id), 0u);
   pending_image_decodes_.erase(image_id);
 
   images_decoded_once_.insert(image_id);
   images_pending_invalidation_.insert(image_id);
   client_->NeedsInvalidationForCheckerImagedTiles();
 }
@@ skipping 52 matching lines @@
   DCHECK_EQ(image_id_to_decode_request_id_.count(image_id), 0U);
 
   image_id_to_decode_request_id_[image_id] =
       image_controller_->QueueImageDecode(
           image, base::Bind(&CheckerImageTracker::DidFinishImageDecode,
                             weak_factory_.GetWeakPtr(), image_id));
   pending_image_decodes_.insert(image_id);
 }
 
 }  // namespace cc