1 files changed, 78 insertions, 0 deletions
diff --git a/cc/scheduler/vsync_time_source.h b/cc/scheduler/vsync_time_source.h
new file mode 100644
index 0000000..4cd0441
--- /dev/null
+++ b/cc/scheduler/vsync_time_source.h
@@ -0,0 +1,78 @@
+// Copyright 2013 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.
+
+#ifndef CC_SCHEDULER_VSYNC_TIME_SOURCE_H_
+#define CC_SCHEDULER_VSYNC_TIME_SOURCE_H_
+
+#include "cc/base/cc_export.h"
+#include "cc/scheduler/time_source.h"
+
+namespace cc {
+
+class CC_EXPORT VSyncClient {
+ public:
+  virtual void DidVSync(base::TimeTicks frame_time) = 0;
+
+ protected:
+  virtual ~VSyncClient() {}
+};
+
+class VSyncProvider {
+ public:
+  // Request to be notified of future vsync events. The notifications will be
+  // delivered until they are disabled by calling this function with a null
+  // client.
+  virtual void RequestVSyncNotification(VSyncClient* client) = 0;
+
+ protected:
+  virtual ~VSyncProvider() {}
+};
+
+// This timer implements a time source that is explicitly triggered by an
+// external vsync signal.
+class CC_EXPORT VSyncTimeSource : public TimeSource, public VSyncClient {
+ public:
+  enum NotificationDisableOption {
+    // The notification will be lazily disabled in the callback to ensure
+    // we get notified of the frame immediately following a quick on-off-on
+    // transition.
+    DISABLE_ON_NEXT_TICK,
+    DISABLE_SYNCHRONOUSLY
+  };
+
+  static scoped_refptr<VSyncTimeSource> Create(
+      VSyncProvider* vsync_provider, NotificationDisableOption option);
+
+  // TimeSource implementation
+  virtual void SetClient(TimeSourceClient* client) OVERRIDE;
+  virtual void SetTimebaseAndInterval(base::TimeTicks timebase,
+                                      base::TimeDelta interval) OVERRIDE;
+  virtual void SetActive(bool active) OVERRIDE;
+  virtual bool Active() const OVERRIDE;
+  virtual base::TimeTicks LastTickTime() OVERRIDE;
+  virtual base::TimeTicks NextTickTime() OVERRIDE;
+
+  // VSyncClient implementation
+  virtual void DidVSync(base::TimeTicks frame_time) OVERRIDE;
+
+ protected:
+  explicit VSyncTimeSource(VSyncProvider* vsync_provider,
+                           NotificationDisableOption option);
+  virtual ~VSyncTimeSource();
+
+  base::TimeTicks last_tick_time_;
+  base::TimeDelta interval_;
+  bool active_;
+  bool notification_requested_;
+
+  VSyncProvider* vsync_provider_;
+  TimeSourceClient* client_;
+  NotificationDisableOption disable_option_;
+
+  DISALLOW_COPY_AND_ASSIGN(VSyncTimeSource);
+};
+
+}  // namespace cc
+
+#endif  // CC_SCHEDULER_VSYNC_TIME_SOURCE_H_