Consolidate volume control code.

ash/accelerators/accelerator_controller_unittest.cc

Index: ash/accelerators/accelerator_controller_unittest.cc
diff --git a/ash/accelerators/accelerator_controller_unittest.cc b/ash/accelerators/accelerator_controller_unittest.cc
index 8b605f190952690f36fda682a6f6d6691d092094..d6c0b63a8b98551d7d592260f12a43d8e48ff345 100644
--- a/ash/accelerators/accelerator_controller_unittest.cc
+++ b/ash/accelerators/accelerator_controller_unittest.cc
@@ -144,6 +144,16 @@ class DummyVolumeControlDelegate : public VolumeControlDelegate {
   }
   virtual void SetVolumePercent(double percent) OVERRIDE {
   }
+  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 {
+  }
 
   int handle_volume_mute_count() const {
     return handle_volume_mute_count_;