Enable keyboard accelerators while a menu is open

ui/views/controls/menu/menu_message_loop_aura.cc

Index: ui/views/controls/menu/menu_message_loop_aura.cc
diff --git a/ui/views/controls/menu/menu_message_loop_aura.cc b/ui/views/controls/menu/menu_message_loop_aura.cc
index 3ed33281aa6f43e8b99a301acb33af9aef39515f..d6ea343b42679c902e433a455751a1a5f266447a 100644
--- a/ui/views/controls/menu/menu_message_loop_aura.cc
+++ b/ui/views/controls/menu/menu_message_loop_aura.cc
@@ -96,6 +96,9 @@ class ActivationChangeObserverImpl
   DISALLOW_COPY_AND_ASSIGN(ActivationChangeObserverImpl);
 };
 
+// The ID that has been given to the last created run_loop.
+int g_last_run_loop_id_ = 0;
+
 }  // namespace
 
 // static
@@ -103,7 +106,9 @@ MenuMessageLoop* MenuMessageLoop::Create() {
   return new MenuMessageLoopAura;
 }
 
-MenuMessageLoopAura::MenuMessageLoopAura() : owner_(NULL) {
+MenuMessageLoopAura::MenuMessageLoopAura()
+    : owner_(NULL),
+      menu_event_filter_(new MenuEventFilter) {
 }
 
 MenuMessageLoopAura::~MenuMessageLoopAura() {
@@ -139,6 +144,11 @@ void MenuMessageLoopAura::Run(MenuController* controller,
   base::AutoReset<base::Closure> reset_quit_closure(&message_loop_quit_,
                                                     base::Closure());
 
+  // The run_loop is about to start, QuitNow() hasn't been called for it yet.
+  int current_run_loop_id = ++g_last_run_loop_id_;
+  run_loop_ids_stack_.push(current_run_loop_id);
+  run_loops_status_[current_run_loop_id] = false;
+
 #if defined(OS_WIN)
   internal::MenuMessagePumpDispatcher nested_dispatcher(controller);
   if (root) {
@@ -157,36 +167,67 @@ void MenuMessageLoopAura::Run(MenuController* controller,
     run_loop.Run();
   }
 #else
-  internal::MenuEventDispatcher event_dispatcher(controller);
-  scoped_ptr<ui::ScopedEventDispatcher> dispatcher_override;
-  if (ui::PlatformEventSource::GetInstance()) {
-    dispatcher_override =
-        ui::PlatformEventSource::GetInstance()->OverrideDispatcher(
-            &event_dispatcher);
-  }
+  DCHECK(menu_event_filter_.get());
+
+  scoped_ptr<ActivationChangeObserverImpl> observer;
+  MenuEventFilter::Delegate* previous_delegate =
+      menu_event_filter_->GetCurrentDelegate();
+
   if (root) {
-    scoped_ptr<ActivationChangeObserverImpl> observer;
     if (!nested_menu)
       observer.reset(new ActivationChangeObserverImpl(controller, root));
-    aura::client::DispatcherRunLoop run_loop(
-        aura::client::GetDispatcherClient(root), NULL);
-    message_loop_quit_ = run_loop.QuitClosure();
-    run_loop.Run();
-  } else {
-    base::MessageLoopForUI* loop = base::MessageLoopForUI::current();
-    base::MessageLoop::ScopedNestableTaskAllower allow(loop);
-    base::RunLoop run_loop;
-    message_loop_quit_ = run_loop.QuitClosure();
-    run_loop.Run();
+    MenuEventFilter::Delegate* filter_delegate =
+        MenuEventFilter::GetMenuEventFilterDelegate(root);
+    if (filter_delegate)
+      menu_event_filter_->SetDelegate(filter_delegate);
   }
-#endif
+
+  aura::Env::GetInstanceDontCreate()->PrependPreTargetHandler(
+      menu_event_filter_.get());
+
+  base::MessageLoopForUI* loop = base::MessageLoopForUI::current();
+  base::MessageLoop::ScopedNestableTaskAllower allow(loop);
+  base::RunLoop run_loop;
+  message_loop_quit_ = run_loop.QuitClosure();
+
+  run_loop.Run();
+
+  // Restore the previous delegate in the case of nested run loops.
+  menu_event_filter_->SetDelegate(previous_delegate);

[pkotwicz, 2015/08/27 17:19:55]

Can we remove the MenuEventFilter pretarget handler here? I don't think that
this will change the behavior from what you currently have except in the case
that we get a key event in between the time that MenuMessageLoopAura::QuitNow()
is called and the time that base::RunLoop quits. I think this is ok.

My understanding based on reading https://codereview.chromium.org/1664001 is
that the interesting behavior in between the time that
MenuMessageLoopAura::QuitNow() is called and the time that base::RunLoop quits
is to make tests pass on Windows

[afakhry, 2015/08/28 01:24:41]

This is an awesome idea! I don't even need to care if QuitNow() is called
multiple times before the run_loop exits, so I removed all the needed code to
achieve that. I don't know why I didn't think of that in the first place.
Done. It's much cleaner and simpler now.

+#endif  // defined(OS_WIN)
+
+  // Now erase this run_loop ID to mark it as returned.
+  run_loops_status_.erase(current_run_loop_id);
+  run_loop_ids_stack_.pop();
 }
 
 void MenuMessageLoopAura::QuitNow() {
   CHECK(!message_loop_quit_.is_null());
+
+  if (run_loop_ids_stack_.empty())
+    return;
+
+  // This RunLoop has already returned? We should not call QuitNow() again.
+  int current_run_loop_id = run_loop_ids_stack_.top();
+  auto itr = run_loops_status_.find(current_run_loop_id);
+  if (itr == run_loops_status_.end())
+    return;
+
+  // QuitNow() has already been called?
+  if (itr->second)
+    return;
+
+  // Overwrite the status so that QuitNow() is marked as called for this
+  // RunLoop.
+  run_loops_status_[current_run_loop_id] = true;
+
   message_loop_quit_.Run();
 
 #if !defined(OS_WIN)
+  aura::Env::GetInstanceDontCreate()->RemovePreTargetHandler(
+      menu_event_filter_.get());
+  menu_event_filter_->ClearDelegate();
+
   // Ask PlatformEventSource to stop dispatching events in this message loop
   // iteration. We want our menu's loop to return before the next event.
   if (ui::PlatformEventSource::GetInstance())