chromeos: Cleanup comments and DEPS in //ash

ash/accelerators/accelerator_controller_delegate_aura.h

Index: ash/accelerators/accelerator_controller_delegate_aura.h
diff --git a/ash/accelerators/accelerator_controller_delegate_aura.h b/ash/accelerators/accelerator_controller_delegate_aura.h
index ea19b01d604aee8338b9fc9b210eed81e5755a90..8c2ecce88ae9fc7cdf0cb643632347c016dcce03 100644
--- a/ash/accelerators/accelerator_controller_delegate_aura.h
+++ b/ash/accelerators/accelerator_controller_delegate_aura.h
@@ -14,9 +14,10 @@ namespace ash {
 
 class ScreenshotDelegate;
 
-// Contains all the accelerators that have dependencies on portions of ash
-// not yet converted to ash/common. When adding a new accelerator that only
-// depends on ash/common code, add it to accelerator_controller.cc instead.
+// Support for accelerators that only work in classic ash and not in mash,
+// for example accelerators related to display management. These sorts of
+// accelerators should be rare. Most new accelerators should be added to
+// accelerator_controller.cc instead.
 class ASH_EXPORT AcceleratorControllerDelegateAura
     : public AcceleratorControllerDelegate {
  public: