Revert of Move beforeunload hang timer duties to its own timer.

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 8c44414cbda911773b920c08a7dd79d3a988a60a..6749aafe832138b29352a637eb1107f508b56817 100644
--- a/content/browser/web_contents/web_contents_impl.cc
+++ b/content/browser/web_contents/web_contents_impl.cc
@@ -4858,6 +4858,16 @@
       "ChildProcess.HangRendererType", type,
       RendererUnresponsiveType::RENDERER_UNRESPONSIVE_MAX);
 
+  RenderFrameHostImpl* rfhi =
+      static_cast<RenderFrameHostImpl*>(GetRenderViewHost()->GetMainFrame());
+  if (rfhi->is_waiting_for_beforeunload_ack()) {
+    // If the hang is in the beforeunload handler, pretend the beforeunload
+    // listeners have all fired and allow the delegate to continue closing;
+    // the user will not have the option of cancelling the close.
+    rfhi->SimulateBeforeUnloadAck();
+    return;
+  }
+
   if (!GetRenderViewHost() || !GetRenderViewHost()->IsRenderViewLive())
     return;