Remove image_decode_tasks_enabled flag.

content/renderer/render_thread_impl.h

Index: content/renderer/render_thread_impl.h
diff --git a/content/renderer/render_thread_impl.h b/content/renderer/render_thread_impl.h
index 5438b78d1e5730b559b099cbd4377caec97b82de..b1ae7a113eb78cce86c8077671292b88234fd4fb 100644
--- a/content/renderer/render_thread_impl.h
+++ b/content/renderer/render_thread_impl.h
@@ -240,7 +240,6 @@ class CONTENT_EXPORT RenderThreadImpl
   GetCompositorImplThreadTaskRunner() override;
   blink::scheduler::RendererScheduler* GetRendererScheduler() override;
   cc::TaskGraphRunner* GetTaskGraphRunner() override;
-  bool AreImageDecodeTasksEnabled() override;
   bool IsThreadedAnimationEnabled() override;
   bool IsScrollAnimatorEnabled() override;
   bool IsSurfaceSynchronizationEnabled() override;
@@ -736,7 +735,6 @@ class CONTENT_EXPORT RenderThreadImpl
   bool is_partial_raster_enabled_;
   bool is_elastic_overscroll_enabled_;
   cc::BufferToTextureTargetMap buffer_to_texture_target_map_;
-  bool are_image_decode_tasks_enabled_;
   bool is_threaded_animation_enabled_;
   bool is_scroll_animator_enabled_;
   bool is_surface_synchronization_enabled_;