TaskGraphRunner Group support

cc/raster/synchronous_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/synchronous_task_graph_runner.h"
 
+#include <algorithm>
+#include <utility>
+
 #include "base/threading/simple_thread.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/trace_event/trace_event.h"
 
 namespace cc {
 
 SynchronousTaskGraphRunner::SynchronousTaskGraphRunner() {}
 
 SynchronousTaskGraphRunner::~SynchronousTaskGraphRunner() {
   DCHECK(!work_queue_.HasReadyToRunTasks());
@@ skipping 17 matching lines @@
 void SynchronousTaskGraphRunner::WaitForTasksToFinishRunning(
     NamespaceToken token) {
   TRACE_EVENT0("cc", "SynchronousTaskGraphRunner::WaitForTasksToFinishRunning");
 
   DCHECK(token.IsValid());
   auto* task_namespace = work_queue_.GetNamespaceForToken(token);
 
   if (!task_namespace)
     return;
 
-  while (
-      !TaskGraphWorkQueue::HasFinishedRunningTasksInNamespace(task_namespace)) {
-    RunTask();
+  while (!work_queue_.HasFinishedRunningTasksInNamespace(task_namespace)) {
+    bool succeeded = RunTask();
+    DCHECK(succeeded);
   }
 }
 
 void SynchronousTaskGraphRunner::CollectCompletedTasks(
     NamespaceToken token,
     Task::Vector* completed_tasks) {
   TRACE_EVENT0("cc", "SynchronousTaskGraphRunner::CollectCompletedTasks");
 
   DCHECK(token.IsValid());
   work_queue_.CollectCompletedTasks(token, completed_tasks);
 }
 
 void SynchronousTaskGraphRunner::RunUntilIdle() {
-  while (work_queue_.HasReadyToRunTasks())
-    RunTask();
+  while (RunTask()) {
+  }
 }
 
-void SynchronousTaskGraphRunner::RunTask() {
+bool SynchronousTaskGraphRunner::RunTask() {
   TRACE_EVENT0("toplevel", "SynchronousTaskGraphRunner::RunTask");
 
-  auto prioritized_task = work_queue_.GetNextTaskToRun();
+  // Find the first category with any tasks to run. This task graph runner
+  // treats categories as an additional priority.
+  const auto& ready_to_run_namespaces = work_queue_.ready_to_run_namespaces();
+  auto found = std::find_if(
+      ready_to_run_namespaces.cbegin(), ready_to_run_namespaces.cend(),
+      [](const std::pair<uint16_t, TaskGraphWorkQueue::TaskNamespace::Vector>&
+             pair) { return !pair.second.empty(); });
+
+  if (found == ready_to_run_namespaces.cend()) {
+    return false;
+  }
+
+  const uint16_t category = found->first;
+  auto prioritized_task = work_queue_.GetNextTaskToRun(category);
 
   Task* task = prioritized_task.task;
   task->WillRun();
   task->RunOnWorkerThread();
   task->DidRun();
 
   work_queue_.CompleteTask(prioritized_task);
+
+  return true;
 }
 
 }  // namespace cc