Don't show current RenderWidgetHostView while interstitial is showing.

content/browser/web_contents/web_contents_impl.h

Index: content/browser/web_contents/web_contents_impl.h
diff --git a/content/browser/web_contents/web_contents_impl.h b/content/browser/web_contents/web_contents_impl.h
index f02483729b5a2a8063c1b5548ec920bc0adeb087..0c3e3cf4e08ef38c4bda038fc7221b0eb9ad144b 100644
--- a/content/browser/web_contents/web_contents_impl.h
+++ b/content/browser/web_contents/web_contents_impl.h
@@ -755,6 +755,7 @@ class CONTENT_EXPORT WebContentsImpl
       RenderViewHost* new_host) override;
   NavigationControllerImpl& GetControllerForRenderManager() override;
   NavigationEntry* GetLastCommittedNavigationEntryForRenderManager() override;
+  InterstitialPageImpl* GetInterstitialForRenderManager() override;
   bool FocusLocationBarByDefault() override;
   void SetFocusToLocationBar(bool select_all) override;
   bool IsHidden() override;
@@ -1359,6 +1360,12 @@ class CONTENT_EXPORT WebContentsImpl
   // See ResumeLoadingCreatedWebContents.
   bool is_resume_pending_;
 
+  // The interstitial page currently shown, if any. Not owned by this class: the
+  // InterstitialPage is self-owned and deletes itself asynchronously when
+  // hidden. Because it may outlive this WebContents, it enters a disabled state
+  // when hidden or preparing for destruction.
+  InterstitialPageImpl* interstitial_page_;
+
   // Data for current page -----------------------------------------------------
 
   // When a title cannot be taken from any entry, this title will be used.