services/ui: Revert CLs that broke Windows.

services/ui/gles2/command_buffer_task_runner.cc

+// Copyright 2014 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 "services/ui/gles2/command_buffer_task_runner.h"
+
+#include "base/bind.h"
+#include "base/threading/thread_task_runner_handle.h"
+#include "services/ui/gles2/command_buffer_driver.h"
+
+namespace ui {
+
+CommandBufferTaskRunner::CommandBufferTaskRunner()
+    : task_runner_(base::ThreadTaskRunnerHandle::Get()),
+      need_post_task_(true) {
+}
+
+bool CommandBufferTaskRunner::PostTask(
+    const CommandBufferDriver* driver,
+    const TaskCallback& task) {
+  base::AutoLock locker(lock_);
+  driver_map_[driver].push_back(task);
+  ScheduleTaskIfNecessaryLocked();
+  return true;
+}
+
+CommandBufferTaskRunner::~CommandBufferTaskRunner() {}
+
+bool CommandBufferTaskRunner::RunOneTaskInternalLocked() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  lock_.AssertAcquired();
+
+  for (auto it = driver_map_.begin(); it != driver_map_.end(); ++it) {
+    if (!it->first->IsScheduled())
+      continue;
+    TaskQueue& task_queue = it->second;
+    DCHECK(!task_queue.empty());
+    const TaskCallback& callback = task_queue.front();
+    bool complete = false;
+    {
+      base::AutoUnlock unlocker(lock_);
+      complete = callback.Run();
+    }
+    if (complete) {
+      // Only remove the task if it is complete.
+      task_queue.pop_front();
+      if (task_queue.empty())
+        driver_map_.erase(it);
+    }
+    return true;
+  }
+  return false;
+}
+
+void CommandBufferTaskRunner::ScheduleTaskIfNecessaryLocked() {
+  lock_.AssertAcquired();
+  if (!need_post_task_)
+    return;
+  task_runner()->PostTask(
+      FROM_HERE,
+      base::Bind(&CommandBufferTaskRunner::RunCommandBufferTask, this));
+  need_post_task_ = false;
+}
+
+void CommandBufferTaskRunner::RunCommandBufferTask() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  base::AutoLock locker(lock_);
+
+  // Try executing all tasks in |driver_map_| until |RunOneTaskInternalLock()|
+  // returns false (Returning false means |driver_map_| is empty or all tasks
+  // in it aren't executable currently).
+  while (RunOneTaskInternalLocked())
+    ;
+  need_post_task_ = true;
+}
+
+}  // namespace ui