TaskGraphRunner Group support

cc/raster/single_thread_task_graph_runner.cc

 // Copyright 2015 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/raster/single_thread_task_graph_runner.h"
 
 #include <string>
 
 #include "base/threading/simple_thread.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/trace_event/trace_event.h"
+#include "cc/raster/task_category.h"
 
 namespace cc {
 
 SingleThreadTaskGraphRunner::SingleThreadTaskGraphRunner()
     : lock_(),
       has_ready_to_run_tasks_cv_(&lock_),
       has_namespaces_with_finished_running_tasks_cv_(&lock_),
       shutdown_(false) {}
 
 SingleThreadTaskGraphRunner::~SingleThreadTaskGraphRunner() {}
@@ skipping 103 matching lines @@
     RunTaskWithLockAcquired();
   }
 }
 
 void SingleThreadTaskGraphRunner::RunTaskWithLockAcquired() {
   TRACE_EVENT0("toplevel",
                "SingleThreadTaskGraphRunner::RunTaskWithLockAcquired");
 
   lock_.AssertAcquired();
 
-  auto prioritized_task = work_queue_.GetNextTaskToRun();
+  // Find the first category with any tasks to run. Categories used by this task
+  // graph runner are ordered by priority.
+  uint16_t category;
+  for (category = 0u; category < kNumTaskCategories; ++category) {
+    if (work_queue_.HasReadyToRunTasksForCategory(category))
+      break;
+  }
+  DCHECK(category < kNumTaskCategories);
+
+  auto prioritized_task = work_queue_.GetNextTaskToRun(category);
   Task* task = prioritized_task.task;
 
   // Call WillRun() before releasing |lock_| and running task.
   task->WillRun();
 
   {
     base::AutoUnlock unlock(lock_);
     task->RunOnWorkerThread();
   }
 
   // This will mark task as finished running.
   task->DidRun();
 
   work_queue_.CompleteTask(prioritized_task);
 
   // If namespace has finished running all tasks, wake up origin thread.
   if (work_queue_.HasFinishedRunningTasksInNamespace(
           prioritized_task.task_namespace))
     has_namespaces_with_finished_running_tasks_cv_.Signal();
 }
 
 }  // namespace cc