Clear Search results in the Mac app launcher on close, rather than launch.

ui/app_list/cocoa/app_list_window_controller.mm

 // Copyright 2013 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.
 
 #import "ui/app_list/cocoa/app_list_window_controller.h"
 
 #include "ui/app_list/app_list_view_delegate.h"
 #import "ui/app_list/cocoa/app_list_view_controller.h"
 #import "ui/app_list/cocoa/apps_grid_controller.h"
+#import "ui/app_list/cocoa/apps_search_box_controller.h"
 #include "ui/base/cocoa/window_size_constants.h"
 
 @interface AppListWindow : NSWindow;
 @end
 
 @implementation AppListWindow
 
 // If we initialize a window with NSBorderlessWindowMask, it will not accept key
 // events (among other things) unless canBecomeKeyWindow is overridden.
 - (BOOL)canBecomeKeyWindow {
@@ skipping 32 matching lines @@
 
 - (AppListViewController*)appListViewController {
   return appListViewController_;
 }
 
 - (void)windowDidResignMain:(NSNotification*)notification {
   if ([appListViewController_ delegate])
     [appListViewController_ delegate]->Dismiss();
 }
 
+- (void)windowWillClose:(NSNotification*)notification {
+  [[appListViewController_ searchBoxController] clearSearch];
+}
+
 @end