cc: Fix crash with blink layout tests and GPU rasterization

We were missing the single-threaded task graph runner, which was
required for blink's layout tests that checked for pixels.

BUG=468928

Review URL: https://codereview.chromium.org/1036693002

Cr-Commit-Position: refs/heads/master@{#322192}

2 files changed, 41 insertions, 11 deletions

diff --git a/cc/trees/layer_tree_host_impl.cc b/cc/trees/layer_tree_host_impl.cc
index 2c13fcb..44c9eed 100644
--- a/cc/trees/layer_tree_host_impl.cc
+++ b/cc/trees/layer_tree_host_impl.cc
@@ -2035,12 +2035,21 @@ void LayerTreeHostImpl::CreateResourceAndTileTaskWorkerPool(
     return;
   }
 
+  // Pass the single-threaded synchronous task graph runner to the worker pool
+  // if we're in synchronous single-threaded mode.
+  TaskGraphRunner* task_graph_runner = task_graph_runner_;
+  if (IsSynchronousSingleThreaded()) {
+    DCHECK(!single_thread_synchronous_task_graph_runner_);
+    single_thread_synchronous_task_graph_runner_.reset(new TaskGraphRunner);
+    task_graph_runner = single_thread_synchronous_task_graph_runner_.get();
+  }
+
   if (use_gpu_rasterization_) {
     *resource_pool =
         ResourcePool::Create(resource_provider_.get(), GL_TEXTURE_2D);
 
     *tile_task_worker_pool = GpuTileTaskWorkerPool::Create(
-        task_runner, task_graph_runner_,
+        task_runner, task_graph_runner,
         static_cast<GpuRasterizer*>(rasterizer_.get()));
     return;
   }
@@ -2058,15 +2067,6 @@ void LayerTreeHostImpl::CreateResourceAndTileTaskWorkerPool(
       *resource_pool =
           ResourcePool::Create(resource_provider_.get(), image_target);
 
-      TaskGraphRunner* task_graph_runner;
-      if (IsSynchronousSingleThreaded()) {
-        DCHECK(!single_thread_synchronous_task_graph_runner_);
-        single_thread_synchronous_task_graph_runner_.reset(new TaskGraphRunner);
-        task_graph_runner = single_thread_synchronous_task_graph_runner_.get();
-      } else {
-        task_graph_runner = task_graph_runner_;
-      }
-
       *tile_task_worker_pool = ZeroCopyTileTaskWorkerPool::Create(
           task_runner, task_graph_runner, resource_provider_.get());
       return;
@@ -2080,7 +2080,7 @@ void LayerTreeHostImpl::CreateResourceAndTileTaskWorkerPool(
           ResourcePool::Create(resource_provider_.get(), GL_TEXTURE_2D);
 
       *tile_task_worker_pool = OneCopyTileTaskWorkerPool::Create(
-          task_runner, task_graph_runner_, context_provider,
+          task_runner, task_graph_runner, context_provider,
           resource_provider_.get(), staging_resource_pool_.get());
       return;
     }
diff --git a/cc/trees/layer_tree_host_pixeltest_synchronous.cc b/cc/trees/layer_tree_host_pixeltest_synchronous.cc
index c22075f..7dd6d7d 100644
--- a/cc/trees/layer_tree_host_pixeltest_synchronous.cc
+++ b/cc/trees/layer_tree_host_pixeltest_synchronous.cc
@@ -44,6 +44,36 @@ TEST_F(LayerTreeHostSynchronousPixelTest, OneContentLayer) {
       PIXEL_TEST_GL, root, base::FilePath(FILE_PATH_LITERAL("green.png")));
 }
 
+class LayerTreeHostSynchronousGPUPixelTest : public LayerTreePixelTest {
+ public:
+  void InitializeSettings(LayerTreeSettings* settings) override {
+    LayerTreePixelTest::InitializeSettings(settings);
+    settings->single_thread_proxy_scheduler = false;
+    settings->gpu_rasterization_enabled = true;
+    settings->gpu_rasterization_forced = true;
+  }
+
+  void BeginTest() override {
+    LayerTreePixelTest::BeginTest();
+    PostCompositeImmediatelyToMainThread();
+  }
+};
+
+TEST_F(LayerTreeHostSynchronousGPUPixelTest, OneContentLayer) {
+  gfx::Size bounds(200, 200);
+
+  FakeContentLayerClient client;
+  SkPaint green_paint;
+  green_paint.setColor(SkColorSetARGB(255, 0, 255, 0));
+  client.add_draw_rect(gfx::RectF(bounds), green_paint);
+  scoped_refptr<PictureLayer> root = PictureLayer::Create(&client);
+  root->SetBounds(bounds);
+  root->SetIsDrawable(true);
+
+  RunSingleThreadedPixelTest(PIXEL_TEST_GL, root,
+                             base::FilePath(FILE_PATH_LITERAL("green.png")));
+}
+
 }  // namespace
 }  // namespace cc