Devtools[LayoutEditor]: Rework layout-editor workflow

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 cb53b318fe5e525f9af0b206f593c5d884721735..b2a837964e2cf857ab5b74bf32c25a2d858b28b5 100644
--- a/Source/core/inspector/InspectorOverlayHost.h
+++ b/Source/core/inspector/InspectorOverlayHost.h
@@ -51,6 +51,7 @@ public:
     void startPropertyChange(const String&);
     void changeProperty(float delta);
     void endPropertyChange();
+    void clearSelection(bool commitChanges);
 
     class Listener : public WillBeGarbageCollectedMixin {
     public:
@@ -60,6 +61,7 @@ public:
         virtual void overlayStartedPropertyChange(const String&) = 0;
         virtual void overlayPropertyChanged(float cssDelta) = 0;
         virtual void overlayEndedPropertyChange() = 0;
+        virtual void overlayClearSelection(bool commitChanges) = 0;
     };
     void setListener(Listener* listener) { m_listener = listener; }