cc: Fix crash while running blink layout tests with GPU rasterization

cc/trees/layer_tree_host_impl.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 <algorithm>
 #include <limits>
 #include <map>
 
@@ skipping 2017 matching lines @@
   ContextProvider* context_provider = output_surface_->context_provider();
   if (!context_provider) {
     *resource_pool =
         ResourcePool::Create(resource_provider_.get(), GL_TEXTURE_2D);
 
     *tile_task_worker_pool = BitmapTileTaskWorkerPool::Create(
         task_runner, task_graph_runner_, resource_provider_.get());
     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;
   }
 
   if (GetRendererCapabilities().using_image) {
     unsigned image_target = settings_.use_image_texture_target;
     DCHECK_IMPLIES(
         image_target == GL_TEXTURE_RECTANGLE_ARB,
         context_provider->ContextCapabilities().gpu.texture_rectangle);
     DCHECK_IMPLIES(
         image_target == GL_TEXTURE_EXTERNAL_OES,
         context_provider->ContextCapabilities().gpu.egl_image_external);
 
     if (settings_.use_zero_copy || IsSynchronousSingleThreaded()) {
       *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;
     }
 
     if (settings_.use_one_copy) {
       // We need to create a staging resource pool when using copy rasterizer.
       *staging_resource_pool =
           ResourcePool::Create(resource_provider_.get(), image_target);
       *resource_pool =
           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;
     }
   }
 
   // Synchronous single-threaded mode depends on tiles being ready to
   // draw when raster is complete.  Therefore, it must use one of zero
   // copy, software raster, or GPU raster (in the branches above).
   DCHECK(!IsSynchronousSingleThreaded());
 
@@ skipping 1370 matching lines @@
   new_target.SetToMin(layer_impl->MaxScrollOffset());
 
   curve->UpdateTarget(
       animation->TrimTimeToCurrentIteration(CurrentBeginFrameArgs().frame_time)
           .InSecondsF(),
       new_target);
 
   return true;
 }
 }  // namespace cc