Don't fire Alt-Search binding when Alt-Search is being used for accessing a modifer key.

ash/accelerators/accelerator_controller.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/accelerators/accelerator_controller.h"
 
 #include <algorithm>
 #include <cmath>
 #include <string>
 
@@ skipping 565 matching lines @@
         // If something else was pressed between the Shift key being pressed
         // and released, then ignore the release of the Shift key.
         return false;
       }
       if (shell->caps_lock_delegate()->IsCapsLockEnabled()) {
         shell->caps_lock_delegate()->SetCapsLockEnabled(false);
         return true;
       }
       return false;
     case TOGGLE_CAPS_LOCK:
+      if (key_code == ui::VKEY_LWIN) {
+        // If something else was pressed between the Search key (LWIN)
+        // being pressed and released, then ignore the release of the
+        // Search key.
+        // TODO(danakj): Releasing Alt first breaks this: crbug.com/166495
+        if (previous_event_type == ui::ET_KEY_RELEASED ||
+            previous_key_code != ui::VKEY_LWIN)
+          return false;
+      }
       shell->caps_lock_delegate()->ToggleCapsLock();
       return true;
     case BRIGHTNESS_DOWN:
       if (brightness_control_delegate_.get())
         return brightness_control_delegate_->HandleBrightnessDown(accelerator);
       break;
     case BRIGHTNESS_UP:
       if (brightness_control_delegate_.get())
         return brightness_control_delegate_->HandleBrightnessUp(accelerator);
       break;
@@ skipping 255 matching lines @@
     keyboard_brightness_control_delegate) {
   keyboard_brightness_control_delegate_ =
       keyboard_brightness_control_delegate.Pass();
 }
 
 bool AcceleratorController::CanHandleAccelerators() const {
   return true;
 }
 
 }  // namespace ash