Remove ShouldBlockShelfAutoHide().

ui/views/bubble/tray_bubble_view.cc

Index: ui/views/bubble/tray_bubble_view.cc
diff --git a/ui/views/bubble/tray_bubble_view.cc b/ui/views/bubble/tray_bubble_view.cc
index 3d7a93eecae09d4b4d6f03ab71aef2e27a33c54c..f8f937e33c3fe23f0ffd697b23c917ffafe54eb9 100644
--- a/ui/views/bubble/tray_bubble_view.cc
+++ b/ui/views/bubble/tray_bubble_view.cc
@@ -49,6 +49,10 @@ BubbleBorder::Arrow GetArrowAlignment(
   return BubbleBorder::RIGHT_BOTTOM;
 }
 
+// Only one TrayBubbleView is visible at a time, but there are cases where the
+// lifetimes of two different bubbles can overlap briefly.
+int g_current_tray_bubble_view_count_ = 0;
+
 }  // namespace
 
 namespace internal {
@@ -181,6 +185,11 @@ TrayBubbleView::InitParams::InitParams(AnchorAlignment anchor_alignment,
 TrayBubbleView::InitParams::InitParams(const InitParams& other) = default;
 
 // static
+bool TrayBubbleView::IsATrayBubbleOpen() {
+  return g_current_tray_bubble_view_count_ > 0;
+}
+
+// static
 TrayBubbleView* TrayBubbleView::Create(View* anchor,
                                        Delegate* delegate,
                                        InitParams* init_params) {
@@ -219,6 +228,9 @@ TrayBubbleView::TrayBubbleView(View* anchor,
 }
 
 TrayBubbleView::~TrayBubbleView() {
+  --g_current_tray_bubble_view_count_;
+  DCHECK_GE(g_current_tray_bubble_view_count_, 0);
+
   mouse_watcher_.reset();
   // Inform host items (models) that their views are being destroyed.
   if (delegate_)
@@ -232,6 +244,8 @@ void TrayBubbleView::InitializeAndShowBubble() {
   GetWidget()->GetNativeWindow()->SetEventTargeter(
       std::unique_ptr<ui::EventTargeter>(new BubbleWindowTargeter(this)));
   UpdateBubble();
+
+  ++g_current_tray_bubble_view_count_;

[sky, 2017/04/21 20:43:49]

Is there a reason you like this here rather than the constructor? Is it because
you only care about actual showing bubbles?

[Evan Stade, 2017/04/22 00:10:25]

yes. In fact the decrement needs to come earlier, in OnWidgetClosing, so I've
moved it there (this created a subtle bug where the shelf wouldn't hide right
away but rather waited until you moved the mouse by a pixel).

This also exposed a bug which I've addressed here:
https://codereview.chromium.org/2834943002/#

 }
 
 void TrayBubbleView::UpdateBubble() {