Remove image_decode_tasks_enabled flag.

cc/test/fake_recording_source.cc

 // Copyright 2015 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/test/fake_recording_source.h"
 
 #include "cc/test/fake_raster_source.h"
 
 namespace cc {
 
 FakeRecordingSource::FakeRecordingSource() : playback_allowed_event_(nullptr) {}
 
 scoped_refptr<RasterSource> FakeRecordingSource::CreateRasterSource(
     bool can_use_lcd) const {
   return FakeRasterSource::CreateFromRecordingSourceWithWaitable(
       this, can_use_lcd, playback_allowed_event_);
 }
 
 bool FakeRecordingSource::EqualsTo(const FakeRecordingSource& other) {
   return size_ == other.size_ &&
          slow_down_raster_scale_factor_for_debug_ ==
              other.slow_down_raster_scale_factor_for_debug_ &&
-         generate_discardable_images_metadata_ ==
-             other.generate_discardable_images_metadata_ &&
          requires_clear_ == other.requires_clear_ &&
          is_solid_color_ == other.is_solid_color_ &&
          clear_canvas_with_debug_color_ ==
              other.clear_canvas_with_debug_color_ &&
          solid_color_ == other.solid_color_ &&
          background_color_ == other.background_color_;
 }
 
 }  // namespace cc