[Mac] Make BookmarkBubbleController is-a BaseBubbleController.

chrome/browser/ui/cocoa/extensions/extension_installed_bubble_controller.mm

 // 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.
 
 #import "chrome/browser/ui/cocoa/extensions/extension_installed_bubble_controller.h"
 
 #include "base/i18n/rtl.h"
 #include "base/mac/bundle_locations.h"
 #include "base/mac/mac_util.h"
 #include "base/sys_string_conversions.h"
@@ skipping 203 matching lines @@
       arrowPoint = [wrenchButton convertPoint:anchor toView:nil];
       break;
     }
     default: {
       NOTREACHED() << "Generic extension type not allowed in install bubble.";
     }
   }
   return arrowPoint;
 }
 
-// We want this to be a child of a browser window.  addChildWindow:
-// (called from this function) will bring the window on-screen;
-// unfortunately, [NSWindowController showWindow:] will also bring it
-// on-screen (but will cause unexpected changes to the window's
-// position).  We cannot have an addChildWindow: and a subsequent
-// showWindow:. Thus, we have our own version.
+// Override -[BaseBubbleController showWindow:] to tweak bubble location and
+// set up UI elements.
 - (void)showWindow:(id)sender {
   // Generic extensions get an infobar rather than a bubble.
   DCHECK(type_ != extension_installed_bubble::kGeneric);
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
   // Load nib and calculate height based on messages to be shown.
   NSWindow* window = [self initializeWindow];
   int newWindowHeight = [self calculateWindowHeight];
   [self.bubble setFrameSize:NSMakeSize(
       NSWidth([[window contentView] bounds]), newWindowHeight)];
@@ skipping 213 matching lines @@
 
 - (NSRect)getExtensionInstalledInfoMsgFrame {
   return [extensionInstalledInfoMsg_ frame];
 }
 
 - (void)extensionUnloaded:(id)sender {
   extension_ = NULL;
 }
 
 @end