Allow menus to stay open during a child view's drag and drop

chrome/browser/ui/views/toolbar/browser_actions_container.cc

Index: chrome/browser/ui/views/toolbar/browser_actions_container.cc
diff --git a/chrome/browser/ui/views/toolbar/browser_actions_container.cc b/chrome/browser/ui/views/toolbar/browser_actions_container.cc
index d935524540f9a19c9e4c5bbd65a5084b5f4304ed..a828fc31d795ee63823600b19924f18f8c1b4f12 100644
--- a/chrome/browser/ui/views/toolbar/browser_actions_container.cc
+++ b/chrome/browser/ui/views/toolbar/browser_actions_container.cc
@@ -42,6 +42,7 @@
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/views/controls/button/label_button_border.h"
+#include "ui/views/controls/menu/menu_controller.h"
 #include "ui/views/controls/resize_area.h"
 #include "ui/views/metrics.h"
 #include "ui/views/painter.h"
@@ -464,6 +465,17 @@ int BrowserActionsContainer::OnDragUpdated(
 
 void BrowserActionsContainer::OnDragExited() {
   StopShowFolderDropMenuTimer();
+  if (in_overflow_mode()) {

[sky, 2014/07/09 16:09:16]

This is too fragile. The menu code should change so that you don't have to do
anything special here, dnd from a view on the menu just works.

I'm not sure of the ideal route to make that happen, I would have to do a bit
more investigation. I'm just getting back from vacation and so rather behind. I
can take a look later in the week or next week if you get stuck.

[Devlin, 2014/07/09 18:03:41]

Okay - let's try this approach.  It seems to fit the requirement of "just
working" from the view's perspective. :)
I'll keep plugging away for a bit, and see what I can come up with.  If nothing
else, the background will be useful.  If you can keep sparing a few minutes here
and there to lemme know if I'm on the right track, that'd be great. :)

+    views::MenuController* controller =
+        views::MenuController::GetActiveInstance();
+    // Notify the controller that we finished our drag.
+    if (controller)
+      controller->set_drag_in_progress(false);
+    // During the drag, the widget lost mouse capture (even though it
+    // conceptually retained it). Reset the capture to this so that future
+    // capture losses (like clicking outside of the menu) register again.
+    GetWidget()->SetCapture(this);
+  }
   drop_indicator_position_ = -1;
   SchedulePaint();
 }
@@ -531,6 +543,14 @@ void BrowserActionsContainer::WriteDragDataForView(View* sender,
                                                    OSExchangeData* data) {
   DCHECK(data);
 
+  if (in_overflow_mode()) {
+    views::MenuController* controller =
+        views::MenuController::GetActiveInstance();
+    // Notify the controller that a drag is in progress so that reported
+    // capture losses are ignored appropriately.
+    if (controller)
+      controller->set_drag_in_progress(true);
+  }
   for (size_t i = 0; i < browser_action_views_.size(); ++i) {
     BrowserActionButton* button = browser_action_views_[i]->button();
     if (button == sender) {