Fire visibilityChange event on out-of-process iframes.

third_party/WebKit/Source/web/WebLocalFrameImpl.cpp

Index: third_party/WebKit/Source/web/WebLocalFrameImpl.cpp
diff --git a/third_party/WebKit/Source/web/WebLocalFrameImpl.cpp b/third_party/WebKit/Source/web/WebLocalFrameImpl.cpp
index e1700405c1e5122136ff2ed3f723771f9d60de75..bc9574c6499461b215ea96c468c3180a80eba4b2 100644
--- a/third_party/WebKit/Source/web/WebLocalFrameImpl.cpp
+++ b/third_party/WebKit/Source/web/WebLocalFrameImpl.cpp
@@ -1817,7 +1817,7 @@ WebLocalFrameImpl* WebLocalFrameImpl::localRoot()
     // when the WebLocalFrame exists but the core LocalFrame does not.
     // TODO(alexmos, dcheng): Clean this up to only calculate this in one place.
     WebLocalFrameImpl* localRoot = this;
-    while (!localRoot->frameWidget())
+    while (localRoot->parent() && localRoot->parent()->isWebLocalFrame())

[dcheng, 2016/05/24 20:38:24]

Why do we have to change this line?

[lfg, 2016/05/24 23:33:51]

After the renderer receives a ViewMsg_Close, the WebFrameWidget is deleted and
this method starts crashing.

         localRoot = toWebLocalFrameImpl(localRoot->parent());
     return localRoot;
 }