Move a bunch of code in content\renderer to the content namespace.

content/renderer/external_popup_menu.h

Index: content/renderer/external_popup_menu.h
===================================================================
--- content/renderer/external_popup_menu.h	(revision 163045)
+++ content/renderer/external_popup_menu.h	(working copy)
@@ -11,11 +11,13 @@
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebExternalPopupMenu.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebPopupMenuInfo.h"
 
-class RenderViewImpl;
 namespace WebKit {
 class WebExternalPopupMenuClient;
 }
 
+namespace content {
+class RenderViewImpl;
+
 class ExternalPopupMenu : public WebKit::WebExternalPopupMenu {
  public:
   ExternalPopupMenu(RenderViewImpl* render_view,
@@ -47,4 +49,6 @@
   DISALLOW_COPY_AND_ASSIGN(ExternalPopupMenu);
 };
 
+}  // namespace content
+
 #endif  // CONTENT_RENDERER_EXTERNAL_POPUP_MENU_H_