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 36b71712621945b2dd1d631db89dcb742d92e0be..de32ac74b86cda3a1a74af230d251067c10c41c3 100644
--- a/third_party/WebKit/Source/core/frame/LocalFrame.cpp
+++ b/third_party/WebKit/Source/core/frame/LocalFrame.cpp
@@ -923,6 +923,18 @@ FrameNavigationDisabler::~FrameNavigationDisabler() {
   m_frame->enableNavigation();
 }
 
+bool LocalFrame::isNavigationAllowed() const {
+  for (const Frame* currentFrame = this; currentFrame;
+       currentFrame = currentFrame->tree().parent()) {
+    if (currentFrame->isLocalFrame() &&

[dcheng, 2017/01/04 23:12:02]

I'd rather keep this non-recursive: I don't like having to downcast to local
frames, and it causes behavior differences between local and remote frames.

[lfg, 2017/01/09 19:04:12]

Done.

+        toLocalFrame(currentFrame)->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();