Fix: tabs slow to response to beforeunload are closed prematurely.

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 3362cc1b63417be749ef6832eabd73c03b175083..de81e78ca4183958deda34669c159a9a4a5fcbde 100644
--- a/content/browser/web_contents/web_contents_impl.cc
+++ b/content/browser/web_contents/web_contents_impl.cc
@@ -4553,8 +4553,16 @@ void WebContentsImpl::RendererUnresponsive(
   if (DevToolsAgentHost::IsDebuggerAttached(this))
     return;
 
-  if (rfhi->is_waiting_for_beforeunload_ack() ||
-      rfhi->IsWaitingForUnloadACK()) {
+  if (rfhi->is_waiting_for_beforeunload_ack()) {
+    // If the hang is in the beforeunload handler,

[Charlie Reis, 2016/05/19 22:11:56]

nit: Fix line wrap.

+    // 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->ForceBeforeUnloadAck();
+    return;
+  }
+
+  if (rfhi->IsWaitingForUnloadACK()) {
     // Hang occurred while firing the beforeunload/unload handler.

[Charlie Reis, 2016/05/19 22:11:56]

nit: Drop "beforeunload/"

     // Pretend the handler fired so tab closing continues as if it had.
     GetRenderViewHost()->set_sudden_termination_allowed(true);
@@ -4562,18 +4570,10 @@ void WebContentsImpl::RendererUnresponsive(
     if (!GetRenderManager()->ShouldCloseTabOnUnresponsiveRenderer())
       return;
 
-    // If the tab hangs in the beforeunload/unload handler there's really
-    // nothing we can do to recover. 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. Otherwise, pretend the unload listeners have all fired and close
+    // If the tab hangs in the unload handler there's really nothing we can do
+    // to recover. Pretend the unload listeners have all fired and close
     // the tab.
-    bool close = true;
-    if (rfhi->is_waiting_for_beforeunload_ack() && delegate_) {
-      delegate_->BeforeUnloadFired(this, true, &close);
-    }
-    if (close)
-      Close();
+    Close();
     return;
   }