Clicking on caption buttons works when WebUI tab strip is open.

Currently, all clicks outside the WebUI tabstrip are swallowed, but
clicking on (for example) the window close button now works whereas
previously it was ignored and only closed the WebUI tabstrip.

Change-Id: I7852dba7b504eb256bc021bcc020f61de598b408
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2209370Reviewed-by: Collin Baker <collinbaker@chromium.org>
Commit-Queue: Dana Fried <dfried@chromium.org>
Cr-Commit-Position: refs/heads/master@{#770710}

chrome/browser/ui/views/frame/webui_tab_strip_container_view.cc

@@ -596,17 +596,24 @@ bool WebUITabStripContainerView::EventShouldPropagate(const ui::Event& event) {
   if (!EventTypeCanCloseTabStrip(located_event->type()))
     return true;
 
-  // If the event is in the container or control buttons, let it be handled.
-  for (views::View* view : {static_cast<views::View*>(this), tab_counter_}) {
-    if (!view)
-      continue;
-
-    const gfx::Rect bounds_in_screen = view->GetBoundsInScreen();
-    const gfx::Point event_location_in_screen =
-        located_event->target()->GetScreenLocation(*located_event);
-    if (bounds_in_screen.Contains(event_location_in_screen))
-      return true;
-  }
+  const gfx::Point event_location_in_screen =
+      located_event->target()->GetScreenLocation(*located_event);
+  const gfx::Rect container_bounds_in_screen = GetBoundsInScreen();
+
+  // Events in the titlebar need to be handled, so that, for example, hitting
+  // close actually closes the window. Since converting into frame coordinates
+  // is fraught, it's easiest to just test relative position - any click above
+  // the tabstrip is in the frame since the tabstrip is the topmost view.
+  if (event_location_in_screen.y() < container_bounds_in_screen.y())
+    return true;
+
+  // Events in the tab strip container need to be handled.
+  if (container_bounds_in_screen.Contains(event_location_in_screen))
+    return true;
+
+  // Events in the tab counter button need to be handled.
+  if (tab_counter_->GetBoundsInScreen().Contains(event_location_in_screen))
+    return true;
 
   // Otherwise, cancel the event and close the container.
   return false;