cc: Move pre-decodes to background worker.

cc/tiles/tile_manager_unittest.cc

Index: cc/tiles/tile_manager_unittest.cc
diff --git a/cc/tiles/tile_manager_unittest.cc b/cc/tiles/tile_manager_unittest.cc
index 5e116400c8feaa614aaa2b6bf294de0d964b3f3e..0c85f4dc50afa6acd20250bc6863cf9633094b59 100644
--- a/cc/tiles/tile_manager_unittest.cc
+++ b/cc/tiles/tile_manager_unittest.cc
@@ -2527,6 +2527,11 @@ TEST_F(CheckerImagingTileManagerTest, BuildsImageDecodeQueueAsExpected) {
       gfx::Rect(rect_to_raster));  // Eventually rect.
   host_impl()->tile_manager()->PrepareTiles(host_impl()->global_tile_state());
 
+  // Finish all raster and dispatch completion callback so that the decode work
+  // for checkered images can be scheduled.
+  static_cast<SynchronousTaskGraphRunner*>(task_graph_runner())->RunUntilIdle();
+  base::RunLoop().RunUntilIdle();
+
   // Run decode tasks to trigger completion of any pending decodes.
   FlushDecodeTasks();
 
@@ -2564,6 +2569,74 @@ TEST_F(CheckerImagingTileManagerTest, BuildsImageDecodeQueueAsExpected) {
   EXPECT_FALSE(host_impl()->client()->did_request_impl_side_invalidation());
 }
 
+TEST_F(CheckerImagingTileManagerTest,
+       TileManagerCorrectlyPrioritizesCheckerImagedDecodes) {
+  gfx::Size layer_bounds(500, 500);
+
+  std::unique_ptr<FakeRecordingSource> recording_source =
+      FakeRecordingSource::CreateFilledRecordingSource(layer_bounds);
+  recording_source->set_fill_with_nonsolid_color(true);
+
+  recording_source->Rerecord();
+  scoped_refptr<RasterSource> raster_source =
+      RasterSource::CreateFromRecordingSource(recording_source.get(), false);
+
+  // Required for activation tiles block checker-imaged decodes.
+  SetupPendingTree(raster_source, gfx::Size(100, 100),
+                   Region(gfx::Rect(0, 0, 500, 500)));
+  host_impl()->tile_manager()->PrepareTiles(host_impl()->global_tile_state());
+  EXPECT_TRUE(host_impl()->tile_manager()->HasScheduledTileTasksForTesting());
+  EXPECT_TRUE(host_impl()
+                  ->tile_manager()
+                  ->checker_image_tracker()
+                  .no_decodes_allowed_for_testing());
+  while (!host_impl()->client()->ready_to_activate()) {
+    static_cast<SynchronousTaskGraphRunner*>(task_graph_runner())
+        ->RunSingleTaskForTesting();
+    base::RunLoop().RunUntilIdle();
+  }
+  EXPECT_EQ(host_impl()
+                ->tile_manager()
+                ->checker_image_tracker()
+                .decode_priority_allowed_for_testing(),
+            CheckerImageTracker::DecodeType::kRaster);
+
+  // Finishing all tasks allows pre-decodes.
+  static_cast<SynchronousTaskGraphRunner*>(task_graph_runner())->RunUntilIdle();
+  base::RunLoop().RunUntilIdle();
+  EXPECT_EQ(host_impl()
+                ->tile_manager()
+                ->checker_image_tracker()
+                .decode_priority_allowed_for_testing(),
+            CheckerImageTracker::DecodeType::kPreDecode);
+
+  // Required for draw tiles block checker-imaged decodes.
+  // Free all tile resources and perform another PrepareTiles.
+  ActivateTree();
+  EXPECT_TRUE(host_impl()->tile_manager()->IsReadyToDraw());
+  host_impl()->tile_manager()->PrepareTiles(
+      GlobalStateThatImpactsTilePriority());
+  EXPECT_FALSE(host_impl()->tile_manager()->IsReadyToDraw());
+
+  host_impl()->client()->reset_ready_to_draw();
+  host_impl()->tile_manager()->PrepareTiles(host_impl()->global_tile_state());
+  EXPECT_TRUE(host_impl()->tile_manager()->HasScheduledTileTasksForTesting());
+  EXPECT_TRUE(host_impl()
+                  ->tile_manager()
+                  ->checker_image_tracker()
+                  .no_decodes_allowed_for_testing());
+  while (!host_impl()->client()->ready_to_draw()) {
+    static_cast<SynchronousTaskGraphRunner*>(task_graph_runner())
+        ->RunSingleTaskForTesting();
+    base::RunLoop().RunUntilIdle();
+  }
+  EXPECT_EQ(host_impl()
+                ->tile_manager()
+                ->checker_image_tracker()
+                .decode_priority_allowed_for_testing(),
+            CheckerImageTracker::DecodeType::kRaster);
+}
+
 class CheckerImagingTileManagerMemoryTest
     : public CheckerImagingTileManagerTest {
  public:
@@ -2636,6 +2709,11 @@ TEST_F(CheckerImagingTileManagerMemoryTest, AddsAllNowTilesToImageDecodeQueue) {
       complete_tiling_rect);  // Eventually rect.
   host_impl()->tile_manager()->PrepareTiles(host_impl()->global_tile_state());
 
+  // Finish all raster work so the decode work for checkered images can be
+  // scheduled.
+  static_cast<SynchronousTaskGraphRunner*>(task_graph_runner())->RunUntilIdle();
+  base::RunLoop().RunUntilIdle();
+
   // Flush all decode tasks. The tiles with checkered images should be
   // invalidated.
   FlushDecodeTasks();