Fix image map focus ring painting

third_party/WebKit/Source/core/html/HTMLAreaElement.h

Index: third_party/WebKit/Source/core/html/HTMLAreaElement.h
diff --git a/third_party/WebKit/Source/core/html/HTMLAreaElement.h b/third_party/WebKit/Source/core/html/HTMLAreaElement.h
index 2fd276aefd03775f6ade306d474e726df01f6ab2..1a85d80ed03ae1302d73394844bda459aba85ff8 100644
--- a/third_party/WebKit/Source/core/html/HTMLAreaElement.h
+++ b/third_party/WebKit/Source/core/html/HTMLAreaElement.h
@@ -40,10 +40,15 @@ public:
 
     bool isDefault() const { return m_shape == Default; }
 
-    bool pointInArea(LayoutPoint, const LayoutSize& containerSize);
-
-    LayoutRect computeRect(const LayoutObject*) const;
-    Path computePath(const LayoutObject*) const;
+    // |containerObject| in the following functions is an object (normally a LayoutImage)
+    // which references the containing image map of this area. There might be multiple
+    // objects referencing the same map. For these functions, the effective geometry of
+    // this map will be calculated based on the specified container object, e.g. the
+    // rectangle of the default shape will be the border box rect of the container object,
+    // and effective zoom factor of the container object will be applied on non-default shape.
+    bool pointInArea(const LayoutPoint&, const LayoutObject* containerObject) const;
+    LayoutRect computeAbsoluteRect(const LayoutObject* containerObject) const;
+    Path getPath(const LayoutObject* containerObject) const;
 
     // The parent map's image.
     HTMLImageElement* imageElement() const;
@@ -60,12 +65,10 @@ private:
     void setFocus(bool) override;
 
     enum Shape { Default, Poly, Rect, Circle };
-    Path getRegion(const LayoutSize&) const;
-    void invalidateCachedRegion();
+    void invalidateCachedPath();
 
-    OwnPtr<Path> m_region;
+    mutable OwnPtr<Path> m_path;
     Vector<double> m_coords;
-    LayoutSize m_lastSize;
     Shape m_shape;
 };