Devtools: Margin resizer in overlay experiment

Source/core/inspector/InspectorOverlayHost.h

Index: Source/core/inspector/InspectorOverlayHost.h
diff --git a/Source/core/inspector/InspectorOverlayHost.h b/Source/core/inspector/InspectorOverlayHost.h
index 58c61b4beef28164d3fa5fc6365e2f88e3198b9e..51b0c93b613428e5d6c729546ea8597b5847889d 100644
--- a/Source/core/inspector/InspectorOverlayHost.h
+++ b/Source/core/inspector/InspectorOverlayHost.h
@@ -48,6 +48,7 @@ public:
 
     void resume();
     void stepOver();
+    void updateCSSProperty(long newValue);
 
     class Listener : public WillBeGarbageCollectedMixin {
     public:
@@ -57,10 +58,19 @@ public:
     };
     void setListener(Listener* listener) { m_listener = listener; }
 
+    class CSSListener : public WillBeGarbageCollectedMixin {
+    public:
+        virtual ~CSSListener() { }
+        virtual void updateCSSProperty(long newValue) = 0;
+    };
+    void setCSSListener(CSSListener* listener) { m_cssListener = listener; }
+
+
 private:
     InspectorOverlayHost();
 
     RawPtrWillBeMember<Listener> m_listener;
+    RawPtrWillBeMember<CSSListener> m_cssListener;
 };
 
 } // namespace blink