cc: Disable image hijack canvas when tiles don't have images.

cc/playback/raster_source.cc

 // Copyright 2014 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/playback/raster_source.h"
 
 #include <stddef.h>
 
 #include "base/strings/stringprintf.h"
 #include "base/thread_task_runner_handle.h"
@@ skipping 82 matching lines @@
                                     const PlaybackSettings& settings) const {
   if (!settings.playback_to_shared_canvas) {
     PrepareForPlaybackToCanvas(raster_canvas, canvas_bitmap_rect,
                                canvas_playback_rect, contents_scale);
   }
 
   if (settings.skip_images) {
     SkipImageCanvas canvas(raster_canvas);
     RasterCommon(&canvas, nullptr, canvas_bitmap_rect, canvas_playback_rect,
                  contents_scale);
-  } else if (settings.use_image_hijack_canvas &&
-             display_list_->MayHaveDiscardableImages()) {
+  } else if (settings.use_image_hijack_canvas) {
     const SkImageInfo& info = raster_canvas->imageInfo();
     ImageHijackCanvas canvas(info.width(), info.height(),
                              image_decode_controller_);
     canvas.addCanvas(raster_canvas);
 
     RasterCommon(&canvas, nullptr, canvas_bitmap_rect, canvas_playback_rect,
                  contents_scale);
   } else {
     RasterCommon(raster_canvas, nullptr, canvas_bitmap_rect,
                  canvas_playback_rect, contents_scale);
@@ skipping 232 matching lines @@
   }
   return true;
 }
 
 RasterSource::PlaybackSettings::PlaybackSettings()
     : playback_to_shared_canvas(false),
       skip_images(false),
       use_image_hijack_canvas(true) {}
 
 }  // namespace cc