Move c/r/extensions/* into extensions namespace

chrome/renderer/extensions/chrome_v8_context_set.h

Index: chrome/renderer/extensions/chrome_v8_context_set.h
diff --git a/chrome/renderer/extensions/chrome_v8_context_set.h b/chrome/renderer/extensions/chrome_v8_context_set.h
index 0699542d1e1ecad264ba700b5b5535477280dc89..934ac445fc68ace88819b0937899319b70fc2654 100644
--- a/chrome/renderer/extensions/chrome_v8_context_set.h
+++ b/chrome/renderer/extensions/chrome_v8_context_set.h
@@ -11,7 +11,6 @@
 #include "base/basictypes.h"
 #include "v8/include/v8.h"
 
-class ChromeV8Context;
 class GURL;
 
 namespace base {
@@ -26,6 +25,9 @@ namespace v8 {
 class Context;
 }
 
+namespace extensions {
+class ChromeV8Context;
+
 // A container of ExtensionBindingsContext. Since calling JavaScript within a
 // context can cause any number of contexts to be created or destroyed, this
 // has additional smarts to help with the set changing underneath callers.
@@ -73,4 +75,6 @@ class ChromeV8ContextSet {
   DISALLOW_COPY_AND_ASSIGN(ChromeV8ContextSet);
 };
 
+}  // namespace extensions
+
 #endif  // CHROME_RENDERER_EXTENSIONS_CHROME_V8_CONTEXT_SET_H_