Provide a way to obtain WebLocalFrameBase from a LocalFrame.

third_party/WebKit/Source/core/frame/WebLocalFrameBase.h

Index: third_party/WebKit/Source/core/frame/WebLocalFrameBase.h
diff --git a/third_party/WebKit/Source/core/frame/WebLocalFrameBase.h b/third_party/WebKit/Source/core/frame/WebLocalFrameBase.h
index 4c412122fca9dcd2ada1ddef45cb69df985a39c3..3e05917358238c3299e9c6652f02c5ddcb1b0c19 100644
--- a/third_party/WebKit/Source/core/frame/WebLocalFrameBase.h
+++ b/third_party/WebKit/Source/core/frame/WebLocalFrameBase.h
@@ -5,10 +5,13 @@
 #ifndef WebLocalFrameBase_h
 #define WebLocalFrameBase_h
 
+#include "core/CoreExport.h"
 #include "public/web/WebLocalFrame.h"
 
 namespace blink {
 
+class LocalFrame;
+
 // WebLocalFrameBase is a temporary class the provides a layer of abstraction
 // for WebLocalFrameImpl. Mehtods that are declared public in WebLocalFrameImpl
 // that are not overrides from WebLocalFrame will be declared pure virtual in
@@ -18,6 +21,10 @@ namespace blink {
 // modules.
 // TODO(slangley): Remove this class once WebLocalFrameImpl is in core/.
 class WebLocalFrameBase : public WebLocalFrame {
+ public:
+  CORE_EXPORT static WebLocalFrameBase* FromFrame(LocalFrame*);
+  CORE_EXPORT static WebLocalFrameBase* FromFrame(LocalFrame&);
+
  protected:
   explicit WebLocalFrameBase(WebTreeScopeType scope) : WebLocalFrame(scope) {}
 };