Quickly close tabs/window with long-running unload handlers.

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 3408d0ac25759ae0bc6c71969f58b02b2665a53a..f2b612c77bed8c1f5a9ae8d3a9b361497008ab59 100644
--- a/content/browser/web_contents/web_contents_impl.cc
+++ b/content/browser/web_contents/web_contents_impl.cc
@@ -358,11 +358,17 @@ WebContentsImpl::~WebContentsImpl() {
   // OnCloseStarted isn't called in unit tests.
   if (!close_start_time_.is_null()) {
     base::TimeTicks now = base::TimeTicks::Now();
+    base::TimeDelta close_time = now - close_start_time_;
+    UMA_HISTOGRAM_TIMES("Tab.Close", close_time);
+
     base::TimeTicks unload_start_time = close_start_time_;
+    base::TimeTicks unload_end_time = now;
     if (!before_unload_end_time_.is_null())
       unload_start_time = before_unload_end_time_;
-    UMA_HISTOGRAM_TIMES("Tab.Close", now - close_start_time_);
-    UMA_HISTOGRAM_TIMES("Tab.Close.UnloadTime", now - unload_start_time);
+    if (!unload_detached_start_time_.is_null())
+      unload_end_time = unload_detached_start_time_;
+    base::TimeDelta unload_time = unload_end_time - unload_start_time;
+    UMA_HISTOGRAM_TIMES("Tab.Close.UnloadTime", unload_time);
   }
 
   FOR_EACH_OBSERVER(WebContentsObserver,
@@ -1743,6 +1749,21 @@ void WebContentsImpl::OnCloseStarted() {
     close_start_time_ = base::TimeTicks::Now();
 }
 
+void WebContentsImpl::OnCloseCanceled() {
+  close_start_time_ = base::TimeTicks();
+  before_unload_end_time_ = base::TimeTicks();
+  unload_detached_start_time_ = base::TimeTicks();
+}
+
+void WebContentsImpl::OnUnloadStarted() {
+  before_unload_end_time_ = base::TimeTicks::Now();
+}
+
+void WebContentsImpl::OnUnloadDetachedStarted() {
+  if (unload_detached_start_time_.is_null())
+    unload_detached_start_time_ = base::TimeTicks::Now();
+}
+
 bool WebContentsImpl::ShouldAcceptDragAndDrop() const {
 #if defined(OS_CHROMEOS)
   // ChromeOS panels (pop-ups) do not take drag-n-drop.
@@ -3270,9 +3291,7 @@ void WebContentsImpl::OnDialogClosed(RenderViewHost* rvh,
     // spinning, since we forced it to start spinning in Navigate.
     DidStopLoading(rvh);
     controller_.DiscardNonCommittedEntries();
-
-    close_start_time_ = base::TimeTicks();
-    before_unload_end_time_ = base::TimeTicks();
+    OnCloseCanceled();
   }
   is_showing_before_unload_dialog_ = false;
   static_cast<RenderViewHostImpl*>(