Allow navigations to frames that aren't being unloaded in the unload handler.

third_party/WebKit/Source/core/frame/LocalFrame.cpp

Index: third_party/WebKit/Source/core/frame/LocalFrame.cpp
diff --git a/third_party/WebKit/Source/core/frame/LocalFrame.cpp b/third_party/WebKit/Source/core/frame/LocalFrame.cpp
index 06675fc43a650521f920fa59bd12e8b2fd423db5..6b913d81beb6edf4acfd4d3af602ae155d29369c 100644
--- a/third_party/WebKit/Source/core/frame/LocalFrame.cpp
+++ b/third_party/WebKit/Source/core/frame/LocalFrame.cpp
@@ -915,6 +915,15 @@ FrameNavigationDisabler::~FrameNavigationDisabler() {
   m_frame->enableNavigation();
 }
 
+bool LocalFrame::isNavigationAllowed() const {
+  for (const Frame* cur = this; cur; cur = cur->tree().parent()) {
+    if (cur->isLocalFrame() && toLocalFrame(cur)->m_navigationDisableCount > 0)
+      return false;
+  }
+
+  return true;
+}
+
 ScopedFrameBlamer::ScopedFrameBlamer(LocalFrame* frame) : m_frame(frame) {
   if (m_frame && m_frame->client() && m_frame->client()->frameBlameContext())
     m_frame->client()->frameBlameContext()->Enter();