cc: GPU rasterize tiles synchronously in PrepareToDraw

cc/resources/gpu_raster_worker_pool.cc

Index: cc/resources/gpu_raster_worker_pool.cc
diff --git a/cc/resources/gpu_raster_worker_pool.cc b/cc/resources/gpu_raster_worker_pool.cc
index d29855ad5c150c92cf64791e607c50fb14cb7043..9bd5f2cac7e86fa4eecf8c9c3afdc0ae3b147aaf 100644
--- a/cc/resources/gpu_raster_worker_pool.cc
+++ b/cc/resources/gpu_raster_worker_pool.cc
@@ -124,6 +124,29 @@ void GpuRasterWorkerPool::Shutdown() {
   task_graph_runner_->WaitForTasksToFinishRunning(namespace_token_);
 }
 
+void GpuRasterWorkerPool::RunTasks(RasterTaskQueue* queue) {
+  ScopedGpuRaster gpu_raster(context_provider_);
+
+  for (auto& item : queue->items) {
+    RasterTask* task = item.task;
+    DCHECK(!task->HasCompleted());
+
+    task->WillSchedule();
+    task->ScheduleOnOriginThread(this);
+    task->DidSchedule();
+
+    task->WillRun();
+    task->RunOnWorkerThread();
+    task->DidRun();
+
+    completed_tasks_.push_back(task);
+  }
+
+  multi_picture_draw_.draw();
+
+  CompleteTasks(completed_tasks_);
+}
+
 void GpuRasterWorkerPool::ScheduleTasks(RasterTaskQueue* queue) {
   TRACE_EVENT0("cc", "GpuRasterWorkerPool::ScheduleTasks");
 
@@ -191,16 +214,18 @@ void GpuRasterWorkerPool::CheckForCompletedTasks() {
 
   task_graph_runner_->CollectCompletedTasks(namespace_token_,
                                             &completed_tasks_);
-  for (Task::Vector::const_iterator it = completed_tasks_.begin();
-       it != completed_tasks_.end();
-       ++it) {
-    RasterizerTask* task = static_cast<RasterizerTask*>(it->get());
+  CompleteTasks(completed_tasks_);
+}
+
+void GpuRasterWorkerPool::CompleteTasks(const Task::Vector& tasks) {
+  for (auto& task : tasks) {
+    RasterTask* raster_task = static_cast<RasterTask*>(task.get());
 
-    task->WillComplete();
-    task->CompleteOnOriginThread(this);
-    task->DidComplete();
+    raster_task->WillComplete();
+    raster_task->CompleteOnOriginThread(this);
+    raster_task->DidComplete();
 
-    task->RunReplyOnOriginThread();
+    raster_task->RunReplyOnOriginThread();
   }
   completed_tasks_.clear();
 }