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

chrome/browser/ui/cocoa/constrained_html_delegate_mac.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.
 
 #include "chrome/browser/ui/webui/constrained_html_ui.h"
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/memory/scoped_nsobject.h"
 #include "chrome/browser/profiles/profile.h"
@@ skipping 74 matching lines @@
     constrained_window_(NULL),
     closed_via_webui_(false) {
   tab_contents_.set_delegate(this);
 
   // Set |this| as a property on the tab contents so that the ConstrainedHtmlUI
   // can get a reference to |this|.
   ConstrainedHtmlUI::GetPropertyAccessor().SetProperty(
       tab_contents_.property_bag(), this);
 
   tab_contents_.controller().LoadURL(delegate->GetDialogContentURL(),
-                                     GURL(), PageTransition::START_PAGE,
+                                     GURL(),
+                                     content::PAGE_TRANSITION_START_PAGE,
                                      std::string());
 
   // Create NSWindow to hold tab_contents in the constrained sheet:
   gfx::Size size;
   delegate->GetDialogSize(&size);
   NSRect frame = NSMakeRect(0, 0, size.width(), size.height());
 
   // |window| is retained by the ConstrainedWindowMacDelegateCustomSheet when
   // the sheet is initialized.
   scoped_nsobject<NSWindow> window;
@@ skipping 48 matching lines @@
   return self;
 }
 
 - (void)sheetDidEnd:(NSWindow*)sheet
          returnCode:(int)returnCode
         contextInfo:(void *)contextInfo {
   [sheet orderOut:self];
 }
 
 @end