ash: Prevent power button events from reaching apps.

ash/accelerators/accelerator_controller.cc

Index: ash/accelerators/accelerator_controller.cc
diff --git a/ash/accelerators/accelerator_controller.cc b/ash/accelerators/accelerator_controller.cc
index dda4f2d15f4ebb37b6965994b23e5ffb0d8579e7..667d1a1cd1eb9445ab42c2ce0d6764d4bdf517b2 100644
--- a/ash/accelerators/accelerator_controller.cc
+++ b/ash/accelerators/accelerator_controller.cc
@@ -685,6 +685,12 @@ bool AcceleratorController::PerformAction(int action,
        return HandleMediaPlayPause();
     case MEDIA_PREV_TRACK:
        return HandleMediaPrevTrack();
+    case POWER_PRESSED:  // fallthrough
+    case POWER_RELEASED:
+       // We don't do anything with these at present, but we consume them to
+       // prevent them from getting passed to apps -- see
+       // http://crbug.com/146609.
+       return true;
 #if !defined(NDEBUG)
     case PRINT_LAYER_HIERARCHY:
       return HandlePrintLayerHierarchy();