Remove image_decode_tasks_enabled flag.

cc/trees/layer_tree_host_impl_unittest.cc

 // Copyright 2011 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/trees/layer_tree_host_impl.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <cmath>
@@ skipping 12299 matching lines @@
 TEST_F(LayerTreeHostImplTest, CheckerImagingTileInvalidation) {
   LayerTreeSettings settings = DefaultSettings();
   settings.enable_checker_imaging = true;
   settings.default_tile_size = gfx::Size(256, 256);
   settings.max_untiled_layer_size = gfx::Size(256, 256);
   CreateHostImpl(settings, CreateCompositorFrameSink());
   gfx::Size layer_size = gfx::Size(750, 750);
 
   std::unique_ptr<FakeRecordingSource> recording_source =
       FakeRecordingSource::CreateFilledRecordingSource(layer_size);
-  recording_source->SetGenerateDiscardableImagesMetadata(true);
   sk_sp<SkImage> checkerable_image =
       CreateDiscardableImage(gfx::Size(500, 500));
   recording_source->add_draw_image(checkerable_image, gfx::Point(0, 0));
 
   SkColor non_solid_color = SkColorSetARGB(128, 45, 56, 67);
   PaintFlags non_solid_flags;
   non_solid_flags.setColor(non_solid_color);
   recording_source->add_draw_rect_with_flags(gfx::Rect(510, 0, 200, 600),
                                              non_solid_flags);
   recording_source->add_draw_rect_with_flags(gfx::Rect(0, 510, 200, 400),
@@ skipping 47 matching lines @@
     else
       EXPECT_FALSE(tile->HasRasterTask());
   }
   Region expected_invalidation(
       raster_source->GetRectForImage(checkerable_image->uniqueID()));
   EXPECT_EQ(expected_invalidation, *(root->GetPendingInvalidation()));
 }
 
 }  // namespace
 }  // namespace cc