Don't call LayoutPart::widgetPositionsUpdated unnecessarily.

third_party/WebKit/Source/core/layout/LayoutPart.h

Index: third_party/WebKit/Source/core/layout/LayoutPart.h
diff --git a/third_party/WebKit/Source/core/layout/LayoutPart.h b/third_party/WebKit/Source/core/layout/LayoutPart.h
index 1cefde91ab3c60798afca54ee489f3ccce4d37a6..608cb487e72fab0d7f5cb1879248fe48bbbfc700 100644
--- a/third_party/WebKit/Source/core/layout/LayoutPart.h
+++ b/third_party/WebKit/Source/core/layout/LayoutPart.h
@@ -47,10 +47,12 @@ public:
     Widget* widget() const;
 
     void updateOnWidgetChange();
-    void updateWidgetPosition();
-    void widgetPositionsUpdated();
+    // Returns true if the geometry changed.
     bool updateWidgetGeometry();
 
+    // Notifies this object that all widgets on the page have been updated.
+    void widgetGeometriesUpdated();
+
     bool isLayoutPart() const final { return true; }
     virtual void paintContents(const PaintInfo&, const LayoutPoint&) const;
 
@@ -68,6 +70,7 @@ protected:
     void invalidatePaintOfSubtreesIfNeeded(PaintInvalidationState&) override;
 
 private:
+    bool updateWidgetGeometryInternal();
     CompositingReasons additionalCompositingReasons() const override;
 
     void willBeDestroyed() final;