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

third_party/WebKit/Source/core/loader/FrameLoader.cpp

Index: third_party/WebKit/Source/core/loader/FrameLoader.cpp
diff --git a/third_party/WebKit/Source/core/loader/FrameLoader.cpp b/third_party/WebKit/Source/core/loader/FrameLoader.cpp
index 23c0121c422682de09655ce209a4a58600b7aa4c..505a1e77808f930919046c60b7d5bd6fc126e7f3 100644
--- a/third_party/WebKit/Source/core/loader/FrameLoader.cpp
+++ b/third_party/WebKit/Source/core/loader/FrameLoader.cpp
@@ -287,7 +287,7 @@ void FrameLoader::saveScrollState() {
 }
 
 void FrameLoader::dispatchUnloadEvent() {
-  NavigationDisablerForUnload navigationDisabler;
+  FrameNavigationDisabler navigationDisabler(*m_frame);
 
   // If the frame is unloading, the provisional loader should no longer be
   // protected. It will be detached soon.
@@ -1085,9 +1085,6 @@ void FrameLoader::load(const FrameLoadRequest& passedRequest,
                        HistoryLoadType historyLoadType) {
   DCHECK(m_frame->document());
 
-  if (!m_frame->isNavigationAllowed())

[lfg, 2016/11/10 00:15:04]

This change has a side effect that javascript: navigations will be allowed if
the frame disallows navigations. I think this should be ok, since the frame is
already executing javascript anyway.

-    return;
-
   if (m_inStopAllLoaders)
     return;
 
@@ -1117,6 +1114,12 @@ void FrameLoader::load(const FrameLoadRequest& passedRequest,
                            ? nullptr
                            : m_frame->findFrameForNavigation(
                                  AtomicString(request.frameName()), *m_frame);
+
+  if (targetFrame && targetFrame->isLocalFrame() &&
+      !toLocalFrame(targetFrame)->isNavigationAllowed()) {
+    return;
+  }
+
   NavigationPolicy policy = navigationPolicyForRequest(request);
   if (targetFrame && targetFrame != m_frame &&
       shouldNavigateTargetFrame(policy)) {
@@ -1552,7 +1555,7 @@ bool FrameLoader::shouldClose(bool isReload) {
 
   bool shouldClose = false;
   {
-    NavigationDisablerForUnload navigationDisabler;
+    FrameNavigationDisabler navigationDisabler(*m_frame);
     size_t i;
 
     bool didAllowNavigation = false;