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

chrome/browser/instant/instant_browsertest.cc

Index: chrome/browser/instant/instant_browsertest.cc
diff --git a/chrome/browser/instant/instant_browsertest.cc b/chrome/browser/instant/instant_browsertest.cc
index 6ef2750070a054b228092f83abaebd9fc0cc338a..3447b8f9e231cf40e789416cee32ff0dbf09416a 100644
--- a/chrome/browser/instant/instant_browsertest.cc
+++ b/chrome/browser/instant/instant_browsertest.cc
@@ -141,7 +141,8 @@ class InstantTest : public InProcessBrowserTest {
   bool SetSuggestionsJavascriptArgument(const std::string& argument) {
     std::wstring script = UTF8ToWide(base::StringPrintf(
         "window.setSuggestionsArgument = %s;", argument.c_str()));
-    RenderViewHost* rvh = preview()->web_contents()->GetRenderViewHost();
+    content::RenderViewHost* rvh =
+        preview()->web_contents()->GetRenderViewHost();
     return ui_test_utils::ExecuteJavaScript(rvh, std::wstring(), script);
   }