Removing the TimeSource abstraction as it is not used anywhere.

cc/scheduler/delay_based_time_source.h

Index: cc/scheduler/delay_based_time_source.h
diff --git a/cc/scheduler/delay_based_time_source.h b/cc/scheduler/delay_based_time_source.h
index a5ea2fb129f251764ea27c3bbc5dc08d54f1ed80..18c8002f2925b746461572c5e31a12526d5ad8d4 100644
--- a/cc/scheduler/delay_based_time_source.h
+++ b/cc/scheduler/delay_based_time_source.h
@@ -10,33 +10,41 @@
 #include "base/memory/weak_ptr.h"
 #include "base/values.h"
 #include "cc/base/cc_export.h"
-#include "cc/scheduler/time_source.h"
 
 namespace base { class SingleThreadTaskRunner; }
 
 namespace cc {
 
+class CC_EXPORT TimeSourceClient {
+ public:
+  virtual void OnTimerTick() = 0;
+
+ protected:
+  virtual ~TimeSourceClient() {}
+};
+
 // This timer implements a time source that achieves the specified interval
 // in face of millisecond-precision delayed callbacks and random queueing
 // delays. DelayBasedTimeSource uses base::TimeTicks::Now as its timebase.
-class CC_EXPORT DelayBasedTimeSource : public TimeSource {
+class CC_EXPORT DelayBasedTimeSource
+    : public base::RefCounted<DelayBasedTimeSource> {
  public:
   static scoped_refptr<DelayBasedTimeSource> Create(
       base::TimeDelta interval, base::SingleThreadTaskRunner* task_runner);
 
-  virtual void SetClient(TimeSourceClient* client) OVERRIDE;
+  virtual void SetClient(TimeSourceClient* client);
 
   // TimeSource implementation
   virtual void SetTimebaseAndInterval(base::TimeTicks timebase,
-                                      base::TimeDelta interval) OVERRIDE;
+                                      base::TimeDelta interval);
 
-  virtual base::TimeTicks SetActive(bool active) OVERRIDE;
-  virtual bool Active() const OVERRIDE;
+  virtual base::TimeTicks SetActive(bool active);
+  virtual bool Active() const;
 
   // Get the last and next tick times. NextTickTime() returns null when
   // inactive.
-  virtual base::TimeTicks LastTickTime() const OVERRIDE;
-  virtual base::TimeTicks NextTickTime() const OVERRIDE;
+  virtual base::TimeTicks LastTickTime() const;
+  virtual base::TimeTicks NextTickTime() const;
 
   // Virtual for testing.
   virtual base::TimeTicks Now() const;
@@ -77,6 +85,7 @@ class CC_EXPORT DelayBasedTimeSource : public TimeSource {
   base::WeakPtrFactory<DelayBasedTimeSource> weak_factory_;
 
  private:
+  friend class base::RefCounted<DelayBasedTimeSource>;
   DISALLOW_COPY_AND_ASSIGN(DelayBasedTimeSource);
 };