Move Render(View|Widget)Host and associated classes to content namespace.

content/browser/tab_contents/web_drag_source_win.h

Index: content/browser/tab_contents/web_drag_source_win.h
diff --git a/content/browser/tab_contents/web_drag_source_win.h b/content/browser/tab_contents/web_drag_source_win.h
index 06580c2a39e89bcf3a66d4bec2fa4a4a2134d69d..68316b64df340f4540c9e9b5425bca09c86999d4 100644
--- a/content/browser/tab_contents/web_drag_source_win.h
+++ b/content/browser/tab_contents/web_drag_source_win.h
@@ -13,9 +13,8 @@
 #include "ui/gfx/native_widget_types.h"
 #include "ui/gfx/point.h"
 
-class RenderViewHost;
-
 namespace content {
+class RenderViewHost;
 class WebContents;
 }
 
@@ -58,7 +57,7 @@ class WebDragSource : public ui::DragSource,
   // We use this as a channel to the renderer to tell it about various drag
   // drop events that it needs to know about (such as when a drag operation it
   // initiated terminates).
-  RenderViewHost* render_view_host_;
+  content::RenderViewHost* render_view_host_;
 
   content::NotificationRegistrar registrar_;