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

chrome/browser/tab_contents/web_drop_target_win.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 "chrome/browser/tab_contents/web_drop_target_win.h"
 
 #include <windows.h>
 #include <shlobj.h>
 
 #include "chrome/browser/bookmarks/bookmark_node_data.h"
@@ skipping 55 matching lines @@
 
   void OnDragLeave(IDataObject* data_object) {
   }
 
   DWORD OnDrop(IDataObject* data_object, DWORD effect) {
     if (ui::ClipboardUtil::HasUrl(data_object)) {
       std::wstring url;
       std::wstring title;
       ui::ClipboardUtil::GetUrl(data_object, &url, &title, true);
       tab_contents_->OpenURL(GURL(url), GURL(), CURRENT_TAB,
-                             PageTransition::AUTO_BOOKMARK);
+                             content::PAGE_TRANSITION_AUTO_BOOKMARK);
       return GetPreferredDropEffect(effect);
     }
     return DROPEFFECT_NONE;
   }
 
  private:
   TabContents* tab_contents_;
 
   DISALLOW_COPY_AND_ASSIGN(InterstitialDropTarget);
 };
@@ skipping 144 matching lines @@
   Browser* browser = Browser::GetBrowserForController(
       &tab_contents_->controller(), NULL);
   if (browser)
     browser->window()->Show();
 
   // This isn't always correct, but at least it's a close approximation.
   // For now, we always map a move to a copy to prevent potential data loss.
   DWORD drop_effect = web_drag_utils_win::WebDragOpToWinDragOp(drag_cursor_);
   return drop_effect != DROPEFFECT_MOVE ? drop_effect : DROPEFFECT_COPY;
 }