Canvas2d: fix event.region being null on mouseleave/out events

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

Index: third_party/WebKit/Source/core/html/HTMLCanvasElement.h
diff --git a/third_party/WebKit/Source/core/html/HTMLCanvasElement.h b/third_party/WebKit/Source/core/html/HTMLCanvasElement.h
index 6c8a1550804f99fdf8c333fda4058e6c05192116..330ee674d6262af2a6a603c3e8c974c275b74fb2 100644
--- a/third_party/WebKit/Source/core/html/HTMLCanvasElement.h
+++ b/third_party/WebKit/Source/core/html/HTMLCanvasElement.h
@@ -187,8 +187,10 @@ public:
 
     void notifyListenersCanvasChanged();
 
+    // For Canvas HitRegions
     bool isSupportedInteractiveCanvasFallback(const Element&);
     std::pair<Element*, String> getControlAndIdIfHitRegionExists(const LayoutPoint&);
+    String getIdFromControl(Element*);

[dtapuska, 2016/04/05 15:57:28]

Is there a requirement that Element be a ptr. Perhaps it would be better to be a
const reference like the isSupportedInteractiveCanvasFallback API..

Can this method be const as well?

[zino, 2016/04/06 11:08:20]

In the current implementation, we are saving the control elements as pointer
type. So, we will finally have to use pointer type to get a hit region
representing control. If needed, we can refactor the related codes to not use
pointer type in follow-up CL.

[dtapuska, 2016/04/06 13:41:25]

That doesn't preclude you from taking the address of the member down in the
HitRegionManager. I'm just looking for a consistent API. It the very least it
should be a const Element*

[zino, 2016/04/06 16:25:38]

Done.

But I used |const_cast| when calling getHitRegionByControl() in
CanvasRenderingContext2D::getIdFromControl().

 
 protected:
     void didMoveToNewDocument(Document& oldDocument) override;