Move addStylesheetByURL from WebFrame to WebLocalFrame.

public/web/WebLocalFrame.h

Index: public/web/WebLocalFrame.h
diff --git a/public/web/WebLocalFrame.h b/public/web/WebLocalFrame.h
index 9636eb37d699c2eb95a98c24ab5ce8f6f9d4135d..333748b65d2f6bb5e8fc7d4dca718c340a539a3e 100644
--- a/public/web/WebLocalFrame.h
+++ b/public/web/WebLocalFrame.h
@@ -31,6 +31,9 @@ public:
     // Returns the frame inside a given frame or iframe element. Returns 0 if
     // the given element is not a frame, iframe or if the frame is empty.
     BLINK_EXPORT static WebLocalFrame* fromFrameOwnerElement(const WebElement&);
+
+    // Navigation Transitions  ---------------------------------------------
+    virtual void addStyleSheetByURL(const WebString& url) = 0;
 };
 
 } // namespace blink