Move c/r/extensions/* into extensions namespace

chrome/renderer/extensions/extension_groups.h

Index: chrome/renderer/extensions/extension_groups.h
diff --git a/chrome/renderer/extensions/extension_groups.h b/chrome/renderer/extensions/extension_groups.h
index c1fd24c4aa27090e6c5f092f3e5f397bffef9431..f5b18da583c575da4b1edead9bd2b3445ab626cf 100644
--- a/chrome/renderer/extensions/extension_groups.h
+++ b/chrome/renderer/extensions/extension_groups.h
@@ -5,6 +5,8 @@
 #ifndef CHROME_RENDERER_EXTENSIONS_EXTENSION_GROUPS_H_
 #define CHROME_RENDERER_EXTENSIONS_EXTENSION_GROUPS_H_
 
+namespace extensions {
+
 // A set of extension groups for use with WebKit::registerExtension and
 // WebFrame::ExecuteScriptInNewWorld to control which extensions get loaded
 // into which contexts.
@@ -13,5 +15,6 @@ enum ExtensionGroups {
   EXTENSION_GROUP_CONTENT_SCRIPTS = 1,
 };
 
+}  // namespace extensions
 
 #endif  // CHROME_RENDERER_EXTENSIONS_EXTENSION_GROUPS_H_