Don't crash when closing interstitial pages.

content/browser/web_contents/web_contents_impl.cc

Index: content/browser/web_contents/web_contents_impl.cc
diff --git a/content/browser/web_contents/web_contents_impl.cc b/content/browser/web_contents/web_contents_impl.cc
index 8aea87eae6df3c70b7b21a7f1ec03a1e53a1b19d..5d4e9003a776fa156fee91a96061c3d3368407a3 100644
--- a/content/browser/web_contents/web_contents_impl.cc
+++ b/content/browser/web_contents/web_contents_impl.cc
@@ -363,6 +363,14 @@ WebContentsImpl::WebContentsImpl(
 WebContentsImpl::~WebContentsImpl() {
   is_being_destroyed_ = true;
 
+  // If there is an interstitial page being shown, tell it to close down early
+  // so that this contents will be alive enough to handle all the UI triggered
+  // by that. <http://crbug.com/363564>
+  InterstitialPageImpl* interstitial_page =
+      static_cast<InterstitialPageImpl*>(GetInterstitialPage());
+  if (interstitial_page)
+    interstitial_page->WebContentsWillBeDestroyed();
+
   // Delete all RFH pending shutdown, which will lead the corresponding RVH to
   // shutdown and be deleted as well.
   frame_tree_.ForEach(
@@ -1769,7 +1777,7 @@ void WebContentsImpl::AttachInterstitialPage(
 }
 
 void WebContentsImpl::DetachInterstitialPage() {
-  if (GetInterstitialPage())
+  if (ShowingInterstitialPage())
     GetRenderManager()->remove_interstitial_page();
   FOR_EACH_OBSERVER(WebContentsObserver, observers_,
                     DidDetachInterstitialPage());