Consolidate volume control code.

ash/wm/system_gesture_event_filter_unittest.cc

Index: ash/wm/system_gesture_event_filter_unittest.cc
diff --git a/ash/wm/system_gesture_event_filter_unittest.cc b/ash/wm/system_gesture_event_filter_unittest.cc
index ed838636a8c10612a6c50bf78ffe26471f485de4..2598bfea702611c0f9deef9d0591c0a69fedfe53 100644
--- a/ash/wm/system_gesture_event_filter_unittest.cc
+++ b/ash/wm/system_gesture_event_filter_unittest.cc
@@ -69,6 +69,17 @@ class DummyVolumeControlDelegate : public VolumeControlDelegate,
   virtual void SetVolumePercent(double percent) OVERRIDE {
     SetPercent(percent);
   }
+  virtual bool IsAudioMuted() const OVERRIDE {
+    return false;
+  }
+  virtual void SetAudioMuted(bool muted) OVERRIDE {
+  }
+  virtual float GetVolumeLevel() const OVERRIDE {
+    return 0.0;
+  }
+  virtual void SetVolumeLevel(float level) OVERRIDE {
+  }
+
 
  private:
   DISALLOW_COPY_AND_ASSIGN(DummyVolumeControlDelegate);