[Mac][MC] Close the tray window when the user clicks outside it.

ui/message_center/cocoa/tray_controller.mm

 // Copyright (c) 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.
 
 #include "ui/message_center/cocoa/tray_controller.h"
 
 #include "ui/base/cocoa/window_size_constants.h"
 #include "ui/base/resource/resource_bundle.h"
 #import "ui/message_center/cocoa/popup_collection.h"
 #import "ui/message_center/cocoa/tray_view_controller.h"
@@ skipping 25 matching lines @@
     [window setDelegate:self];
     [window setHasShadow:YES];
     [window setHidesOnDeactivate:NO];
     [window setLevel:NSFloatingWindowLevel];
 
     viewController_.reset([[MCTrayViewController alloc] initWithMessageCenter:
         tray_->message_center()]);
     NSView* contentView = [viewController_ view];
     [window setFrame:[contentView frame] display:NO];
     [window setContentView:contentView];
+
+    // The global event monitor will close the tray in response to events
+    // delivered to other applications, and -windowDidResignKey: will catch
+    // events within the application.
+    clickEventMonitor_ =
+        [NSEvent addGlobalMonitorForEventsMatchingMask:NSLeftMouseDownMask |
+                                                       NSRightMouseDownMask |
+                                                       NSOtherMouseDownMask
+            handler:^(NSEvent* event) {
+                tray_->HideMessageCenterBubble();
+            }];
   }
   return self;
 }
 
+- (void)dealloc {
+  [NSEvent removeMonitor:clickEventMonitor_];
+  [super dealloc];
+}
+
 - (void)showTrayAt:(NSPoint)point {
   NSRect frame = [[viewController_ view] frame];
   frame.origin.x = point.x;
   frame.origin.y = point.y - NSHeight(frame);
   [[self window] setFrame:frame display:YES];
   [self showWindow:nil];
 }
 
 - (void)onMessageCenterTrayChanged {
   CGFloat oldHeight = NSHeight([[viewController_ view] frame]);
   [viewController_ onMessageCenterTrayChanged];
   CGFloat newHeight = NSHeight([[viewController_ view] frame]);
 
   NSRect windowFrame = [[self window] frame];
   CGFloat delta = newHeight - oldHeight;
   windowFrame.origin.y -= delta;
   windowFrame.size.height += delta;
   [[self window] setFrame:windowFrame display:YES];
 }
 
 - (void)windowDidResignKey:(NSNotification*)notification {
   tray_->HideMessageCenterBubble();
 }
 
 @end