Remove image_decode_tasks_enabled flag.

cc/test/fake_recording_source.cc

Index: cc/test/fake_recording_source.cc
diff --git a/cc/test/fake_recording_source.cc b/cc/test/fake_recording_source.cc
index 011916781c2a649fe8717390c0e33ff0d6d1e885..7f0054a9ad7b6a56f627248b159f0d926cf18f8a 100644
--- a/cc/test/fake_recording_source.cc
+++ b/cc/test/fake_recording_source.cc
@@ -20,8 +20,6 @@ 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_ ==