Move page closing hang timer duties to its own timer.

content/browser/renderer_host/render_view_host_impl.h

Index: content/browser/renderer_host/render_view_host_impl.h
diff --git a/content/browser/renderer_host/render_view_host_impl.h b/content/browser/renderer_host/render_view_host_impl.h
index fece1e032e82f9997b5b2bcd6265e21712e65756..bcc702b2b4f44508d50894ed828b23dd9ebd3369 100644
--- a/content/browser/renderer_host/render_view_host_impl.h
+++ b/content/browser/renderer_host/render_view_host_impl.h
@@ -36,6 +36,7 @@
 namespace content {
 
 struct FrameReplicationState;
+class TimeoutMonitor;
 
 // This implements the RenderViewHost interface that is exposed to
 // embedders of content, and adds things only visible to content.
@@ -252,11 +253,16 @@ class CONTENT_EXPORT RenderViewHostImpl : public RenderViewHost,
   FRIEND_TEST_ALL_PREFIXES(RenderViewHostTest, RoutingIdSane);
   FRIEND_TEST_ALL_PREFIXES(RenderFrameHostManagerTest,
                            CleanUpSwappedOutRVHOnProcessCrash);
+  FRIEND_TEST_ALL_PREFIXES(RenderFrameHostManagerTest,
+                           CloseWithPendingWhileUnresponsive);
   FRIEND_TEST_ALL_PREFIXES(SitePerProcessBrowserTest,
                            NavigateMainFrameToChildSite);
 
   void RenderViewReady();
 
+  // Called by |close_timeout_| when the page closing timeout fires.
+  void ClosePageTimeout();
+
   // TODO(creis): Move to a private namespace on RenderFrameHostImpl.
   // Delay to wait on closing the WebContents for a beforeunload/unload handler
   // to fire.
@@ -312,6 +318,12 @@ class CONTENT_EXPORT RenderViewHostImpl : public RenderViewHost,
   // values depend on.
   std::unique_ptr<WebPreferences> web_preferences_;
 
+  // The timeout monitor that runs from when the page close is started in
+  // ClosePage() until either the render process ACKs the close with an IPC to
+  // OnClosePageACK(), or until the timeout triggers and the page is forcibly
+  // closed.
+  std::unique_ptr<TimeoutMonitor> close_timeout_;
+
   bool updating_web_preferences_;
 
   bool render_view_ready_on_process_launch_;