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

content/browser/webui/generic_handler.cc

 // 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 "content/browser/webui/generic_handler.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/logging.h"
 #include "base/values.h"
@@ skipping 40 matching lines @@
   CHECK(button == 0.0 || button == 1.0);
   bool middle_button = (button == 1.0);
 
   WindowOpenDisposition disposition =
       disposition_utils::DispositionFromClick(middle_button, alt_key, ctrl_key,
                                               meta_key, shift_key);
   if (disposition == CURRENT_TAB && target_string == "_blank")
     disposition = NEW_FOREGROUND_TAB;
 
   web_ui_->tab_contents()->OpenURL(
-      GURL(url_string), GURL(), disposition, PageTransition::LINK);
+      GURL(url_string), GURL(), disposition, content::PAGE_TRANSITION_LINK);
 
   // This may delete us!
 }
 
 void GenericHandler::HandleSetIsLoading(const base::ListValue* args) {
   CHECK(args->GetSize() == 1);
   std::string is_loading;
   CHECK(args->GetString(0, &is_loading));
 
   SetIsLoading(is_loading == "true");
 }
 
 void GenericHandler::SetIsLoading(bool is_loading) {
   DCHECK(web_ui_);
 
   TabContents* contents = web_ui_->tab_contents();
   bool was_loading = contents->IsLoading();
 
   is_loading_ = is_loading;
   if (was_loading != contents->IsLoading())
     contents->delegate()->LoadingStateChanged(contents);
 }