Add preliminary support for hw-accelerated tile rasterization.

cc/resources/pixel_buffer_raster_worker_pool.cc

Index: cc/resources/pixel_buffer_raster_worker_pool.cc
diff --git a/cc/resources/pixel_buffer_raster_worker_pool.cc b/cc/resources/pixel_buffer_raster_worker_pool.cc
index 011e5147e066e4c3e294aceb14ae22bc0b931f31..d72e5a4b12c64e63b6f9e537ef485e8de45a2dcf 100644
--- a/cc/resources/pixel_buffer_raster_worker_pool.cc
+++ b/cc/resources/pixel_buffer_raster_worker_pool.cc
@@ -91,9 +91,10 @@ bool WasCanceled(const internal::RasterWorkerPoolTask* task) {
 
 PixelBufferRasterWorkerPool::PixelBufferRasterWorkerPool(
     ResourceProvider* resource_provider,
+    ContextProvider* context_provider,
     size_t num_threads,
     size_t max_transfer_buffer_usage_bytes)
-    : RasterWorkerPool(resource_provider, num_threads),
+    : RasterWorkerPool(resource_provider, context_provider, num_threads),
       shutdown_(false),
       scheduled_raster_task_count_(0),
       bytes_pending_upload_(0),
@@ -149,6 +150,7 @@ void PixelBufferRasterWorkerPool::ScheduleTasks(RasterTask::Queue* queue) {
 
   // Build new pixel buffer task set.
   TaskMap new_pixel_buffer_tasks;
+  RasterTaskVector gpu_raster_tasks;
   for (RasterTaskVector::const_iterator it = raster_tasks().begin();
        it != raster_tasks().end(); ++it) {
     internal::RasterWorkerPoolTask* task = it->get();
@@ -156,6 +158,11 @@ void PixelBufferRasterWorkerPool::ScheduleTasks(RasterTask::Queue* queue) {
     DCHECK(!task->HasCompleted());
     DCHECK(!task->WasCanceled());
 
+    if (task->use_gpu_rasterization()) {
+      gpu_raster_tasks.push_back(task);
+      continue;
+    }
+
     new_pixel_buffer_tasks[task] = pixel_buffer_tasks_[task];
     pixel_buffer_tasks_.erase(task);
 
@@ -212,6 +219,8 @@ void PixelBufferRasterWorkerPool::ScheduleTasks(RasterTask::Queue* queue) {
   check_for_completed_raster_tasks_pending_ = false;
   ScheduleCheckForCompletedRasterTasks();
 
+  RunGpuRasterTasks(&gpu_raster_tasks);
+
   TRACE_EVENT_ASYNC_STEP_INTO1(
       "cc", "ScheduledTasks", this, StateName(),
       "state", TracedValue::FromValue(StateAsValue().release()));
@@ -584,6 +593,7 @@ void PixelBufferRasterWorkerPool::OnRasterTaskCompleted(
                "was_canceled", was_canceled,
                "needs_upload", needs_upload);
 
+  DCHECK(!task->use_gpu_rasterization());
   DCHECK(pixel_buffer_tasks_.find(task.get()) != pixel_buffer_tasks_.end());
 
   // Balanced with MapPixelBuffer() call in ScheduleMoreTasks().