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

chrome/browser/extensions/extension_webnavigation_api.cc

Index: chrome/browser/extensions/extension_webnavigation_api.cc
diff --git a/chrome/browser/extensions/extension_webnavigation_api.cc b/chrome/browser/extensions/extension_webnavigation_api.cc
index 25956fd8f983e8f3af30947cb4212a1790f2f84d..0b365c315f12e9e63a0a1938e20ac7524fbb2345 100644
--- a/chrome/browser/extensions/extension_webnavigation_api.cc
+++ b/chrome/browser/extensions/extension_webnavigation_api.cc
@@ -557,7 +557,7 @@ void ExtensionWebNavigationTabObserver::DidStartProvisionalLoadForFrame(
     bool is_main_frame,
     const GURL& validated_url,
     bool is_error_page,
-    RenderViewHost* render_view_host) {
+    content::RenderViewHost* render_view_host) {
   // Ignore navigations of sub frames, if the main frame isn't committed yet.
   // This might happen if a sub frame triggers a navigation for both the main
   // frame and itself. Since the sub frame is about to be deleted, and there's