Cherry-pick WebKit change 93521 to fix FrameLoader

See http://trac.webkit.org/changeset/93521

Note that the change did not apply cleanly to
FrameLoader::stopLoading() because we don't have
http://trac.webkit.org/changeset/90164. See bug for details.

Bug: 5264509
Change-Id: I824284b9daaa8bc033aebca558d5362ebfb617d8

1 files changed, 27 insertions, 8 deletions

diff --git a/Source/WebCore/loader/FrameLoader.cpp b/Source/WebCore/loader/FrameLoader.cpp
index dcaf03a..2def2a6 100644
--- a/Source/WebCore/loader/FrameLoader.cpp
+++ b/Source/WebCore/loader/FrameLoader.cpp
@@ -381,8 +381,11 @@ void FrameLoader::stopLoading(UnloadEventPolicy unloadEventPolicy)
                 Node* currentFocusedNode = m_frame->document()->focusedNode();
                 if (currentFocusedNode)
                     currentFocusedNode->aboutToUnload();
-                m_pageDismissalEventBeingDispatched = true;
-                if (m_frame->domWindow()) {
+// ANDROID
+                // See http://b/issue?id=5264509
+                if (m_frame->domWindow() && !m_pageDismissalEventBeingDispatched) {
+                    m_pageDismissalEventBeingDispatched = true;
+// END ANDROID
                     if (unloadEventPolicy == UnloadEventPolicyUnloadAndPageHide)
                         m_frame->domWindow()->dispatchEvent(PageTransitionEvent::create(eventNames().pagehideEvent, m_frame->document()->inPageCache()), m_frame->document());
                     if (!m_frame->document()->inPageCache()) {
@@ -1837,6 +1840,20 @@ void FrameLoader::setDocumentLoader(DocumentLoader* loader)
         m_documentLoader->detachFromFrame();
 
     m_documentLoader = loader;
+
+    // The following abomination is brought to you by the unload event.
+    // The detachChildren() call above may trigger a child frame's unload event,
+    // which could do something obnoxious like call document.write("") on
+    // the main frame, which results in detaching children while detaching children.
+    // This can cause the new m_documentLoader to be detached from its Frame*, but still
+    // be alive. To make matters worse, DocumentLoaders with a null Frame* aren't supposed
+    // to happen when they're still alive (and many places below us on the stack think the
+    // DocumentLoader is still usable). Ergo, we reattach loader to its Frame, and pretend
+    // like nothing ever happened.
+    if (m_documentLoader && !m_documentLoader->frame()) {
+        ASSERT(!m_documentLoader->isLoading());
+        m_documentLoader->setFrame(m_frame);
+    }
 }
 
 void FrameLoader::setPolicyDocumentLoader(DocumentLoader* loader)
@@ -2563,12 +2580,14 @@ void FrameLoader::frameLoadCompleted()
 
 void FrameLoader::detachChildren()
 {
-    // FIXME: Is it really necessary to do this in reverse order?
-    Frame* previous;
-    for (Frame* child = m_frame->tree()->lastChild(); child; child = previous) {
-        previous = child->tree()->previousSibling();
-        child->loader()->detachFromParent();
-    }
+    typedef Vector<RefPtr<Frame> > FrameVector;
+    FrameVector childrenToDetach;
+    childrenToDetach.reserveCapacity(m_frame->tree()->childCount());
+    for (Frame* child = m_frame->tree()->lastChild(); child; child = child->tree()->previousSibling())
+        childrenToDetach.append(child);
+    FrameVector::iterator end = childrenToDetach.end();
+    for (FrameVector::iterator it = childrenToDetach.begin(); it != end; it++)
+        (*it)->loader()->detachFromParent();
 }
 
 void FrameLoader::closeAndRemoveChild(Frame* child)