Move PageTransition into content namespace. While I'm touching all these files, I've also updated...

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

 // Copyright (c) 2011 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_install_dialog_controller.h"
 
 #include "base/mac/mac_util.h"
 #include "base/memory/scoped_nsobject.h"
 #include "base/string_util.h"
 #include "base/sys_string_conversions.h"
@@ skipping 107 matching lines @@
      modalForWindow:parentWindow_
       modalDelegate:self
      didEndSelector:@selector(didEndSheet:returnCode:contextInfo:)
         contextInfo:nil];
 }
 
 - (IBAction)storeLinkClicked:(id)sender {
   GURL store_url(
       extension_urls::GetWebstoreItemDetailURLPrefix() + extension_->id());
   BrowserList::GetLastActiveWithProfile(profile_)->
-      OpenURL(store_url, GURL(), NEW_FOREGROUND_TAB, PageTransition::LINK);
+      OpenURL(store_url, GURL(), NEW_FOREGROUND_TAB,
+      content::PAGE_TRANSITION_LINK);
 
   delegate_->InstallUIAbort(/*user_initiated=*/true);
   [NSApp endSheet:[self window]];
 }
 
 - (IBAction)cancel:(id)sender {
   delegate_->InstallUIAbort(/*user_initiated=*/true);
   [NSApp endSheet:[self window]];
 }
 
@@ skipping 173 matching lines @@
         initWithParentWindow:native_window
                      profile:profile
                    extension:extension
                     delegate:delegate
                         icon:icon
                       prompt:prompt];
 
   // TODO(mihaip): Switch this to be tab-modal (http://crbug.com/95455)
   [controller runAsModalSheet];
 }