Enables hot-tracking for overflow extension buttons in the app menu

ui/views/controls/menu/menu_controller.cc

Index: ui/views/controls/menu/menu_controller.cc
diff --git a/ui/views/controls/menu/menu_controller.cc b/ui/views/controls/menu/menu_controller.cc
index 1cd057e8dcfc1e33813236383bba75570df59295..581fbb974aba5d1ee1eafc7ef61d282b74084786 100644
--- a/ui/views/controls/menu/menu_controller.cc
+++ b/ui/views/controls/menu/menu_controller.cc
@@ -53,16 +53,6 @@ using base::Time;
 using base::TimeDelta;
 using ui::OSExchangeData;
 
-// Period of the scroll timer (in milliseconds).
-static const int kScrollTimerMS = 30;
-
-// Amount of time from when the drop exits the menu and the menu is hidden.
-static const int kCloseOnExitTime = 1200;
-
-// If a context menu is invoked by touch, we shift the menu by this offset so
-// that the finger does not obscure the menu.
-static const int kCenteredContextMenuYOffset = -15;
-
 namespace views {
 
 namespace {
@@ -70,7 +60,17 @@ namespace {
 // When showing context menu on mouse down, the user might accidentally select
 // the menu item on the subsequent mouse up. To prevent this, we add the
 // following delay before the user is able to select an item.
-static int menu_selection_hold_time_ms = kMinimumMsPressedToActivate;
+int menu_selection_hold_time_ms = kMinimumMsPressedToActivate;
+
+// Period of the scroll timer (in milliseconds).
+const int kScrollTimerMS = 30;
+
+// Amount of time from when the drop exits the menu and the menu is hidden.
+const int kCloseOnExitTime = 1200;
+
+// If a context menu is invoked by touch, we shift the menu by this offset so
+// that the finger does not obscure the menu.
+const int kCenteredContextMenuYOffset = -15;
 
 // The spacing offset for the bubble tip.
 const int kBubbleTipSizeLeftRight = 12;
@@ -97,7 +97,7 @@ bool TitleMatchesMnemonic(MenuItemView* menu, base::char16 key) {
 }
 
 // Returns the first descendant of |view| that is hot tracked.
-static CustomButton* GetFirstHotTrackedView(View* view) {
+CustomButton* GetFirstHotTrackedView(View* view) {
   if (!view)
     return NULL;
   CustomButton* button = CustomButton::AsCustomButton(view);
@@ -114,12 +114,31 @@ static CustomButton* GetFirstHotTrackedView(View* view) {
   return NULL;
 }
 
+// Returns a CustomButton descendant of |view| that is (a) hot-tracked and
+// (b) not equal to |hot_button|. Returns null if such descendant is not found.
+// This allows a caller to detect when a button is set to be hot-tracked by a
+// mouse event and its |hot_button_| indicator becomes stale.
+CustomButton* OtherHotTrackedButton(View* view, CustomButton* hot_button) {

[sky, 2016/02/19 01:07:14]

GetFirstHotTrackedViewDifferingFrom (which better explains what this does).

[varkha, 2016/02/23 00:41:05]

Done.

+  if (!view)
+    return nullptr;
+  CustomButton* button = CustomButton::AsCustomButton(view);
+  if (button && button != hot_button && button->IsHotTracked())
+    return button;
+
+  for (int i = 0; i < view->child_count(); ++i) {
+    button = OtherHotTrackedButton(view->child_at(i), hot_button);
+    if (button)
+      return button;
+  }
+  return nullptr;
+}
+
 // Recurses through the child views of |view| returning the first view starting
 // at |start| that is focusable. A value of -1 for |start| indicates to start at
 // the first view (if |forward| is false, iterating starts at the last view). If
 // |forward| is true the children are considered first to last, otherwise last
 // to first.
-static View* GetFirstFocusableView(View* view, int start, bool forward) {
+View* GetFirstFocusableView(View* view, int start, bool forward) {
   if (forward) {
     for (int i = start == -1 ? 0 : start; i < view->child_count(); ++i) {
       View* deepest = GetFirstFocusableView(view->child_at(i), -1, forward);
@@ -137,15 +156,13 @@ static View* GetFirstFocusableView(View* view, int start, bool forward) {
 }
 
 // Returns the first child of |start| that is focusable.
-static View* GetInitialFocusableView(View* start, bool forward) {
+View* GetInitialFocusableView(View* start, bool forward) {
   return GetFirstFocusableView(start, -1, forward);
 }
 
 // Returns the next view after |start_at| that is focusable. Returns NULL if
 // there are no focusable children of |ancestor| after |start_at|.
-static View* GetNextFocusableView(View* ancestor,
-                                  View* start_at,
-                                  bool forward) {
+View* GetNextFocusableView(View* ancestor, View* start_at, bool forward) {
   DCHECK(ancestor->Contains(start_at));
   View* parent = start_at;
   do {
@@ -939,7 +956,13 @@ void MenuController::SetSelection(MenuItemView* menu_item,
   if (pending_item_changed && pending_state_.item) {
     CustomButton* button = GetFirstHotTrackedView(pending_state_.item);
     if (button)
-      button->SetHotTracked(false);
+      SetHotTrackedButton(button, false);
+  }
+  CustomButton* new_hot_button = OtherHotTrackedButton(menu_item, hot_button_);

[sky, 2016/02/19 01:07:14]

It isn't obvious to me why are you doing this. Please add a comment.

[varkha, 2016/02/23 00:41:05]

Done.

+  if (new_hot_button) {
+    if (hot_button_)
+      SetHotTrackedButton(hot_button_, false);
+    SetHotTrackedButton(new_hot_button, true);
   }
 
   // Notify the old path it isn't selected.
@@ -1191,6 +1214,7 @@ MenuController::MenuController(bool blocking,
       last_drop_operation_(MenuDelegate::DROP_UNKNOWN),
       showing_submenu_(false),
       active_mouse_view_id_(ViewStorage::GetInstance()->CreateStorageID()),
+      hot_button_(nullptr),
       delegate_(delegate),
       message_loop_depth_(0),
       closing_event_time_(base::TimeDelta()),
@@ -1226,8 +1250,7 @@ bool MenuController::SendAcceleratorToHotTrackedView() {
 
   ui::Accelerator accelerator(ui::VKEY_RETURN, ui::EF_NONE);
   hot_view->AcceleratorPressed(accelerator);
-  CustomButton* button = static_cast<CustomButton*>(hot_view);
-  button->SetHotTracked(true);
+  SetHotTrackedButton(hot_view, true);
   return true;
 }
 
@@ -1989,8 +2012,7 @@ void MenuController::IncrementSelection(
     // select the first menu item that is visible and enabled.
     if (item->GetSubmenu()->GetMenuItemCount()) {
       MenuItemView* to_select = FindInitialSelectableMenuItem(item, direction);
-      if (to_select)
-        SetSelection(to_select, SELECTION_DEFAULT);
+      SetInitialHotTrackedView(to_select, direction);
       return;
     }
   }
@@ -1998,20 +2020,20 @@ void MenuController::IncrementSelection(
   if (item->has_children()) {
     CustomButton* button = GetFirstHotTrackedView(item);
     if (button) {
-      button->SetHotTracked(false);
-      View* to_make_hot = GetNextFocusableView(
+      SetHotTrackedButton(button, false);
+      View* hot_view = GetNextFocusableView(
           item, button, direction == INCREMENT_SELECTION_DOWN);
-      CustomButton* button_hot = CustomButton::AsCustomButton(to_make_hot);
-      if (button_hot) {
-        button_hot->SetHotTracked(true);
+      CustomButton* hot_button = CustomButton::AsCustomButton(hot_view);
+      if (hot_button) {
+        SetHotTrackedButton(hot_button, true);
         return;
       }
     } else {
-      View* to_make_hot =
+      View* hot_view =
           GetInitialFocusableView(item, direction == INCREMENT_SELECTION_DOWN);
-      CustomButton* button_hot = CustomButton::AsCustomButton(to_make_hot);
-      if (button_hot) {
-        button_hot->SetHotTracked(true);
+      CustomButton* hot_button = CustomButton::AsCustomButton(hot_view);
+      if (hot_button) {
+        SetHotTrackedButton(hot_button, true);
         return;
       }
     }
@@ -2025,14 +2047,7 @@ void MenuController::IncrementSelection(
         if (parent->GetSubmenu()->GetMenuItemAt(i) == item) {
           MenuItemView* to_select =
               FindNextSelectableMenuItem(parent, i, direction);
-          if (!to_select)
-            break;
-          SetSelection(to_select, SELECTION_DEFAULT);
-          View* to_make_hot = GetInitialFocusableView(
-              to_select, direction == INCREMENT_SELECTION_DOWN);
-          CustomButton* button_hot = CustomButton::AsCustomButton(to_make_hot);
-          if (button_hot)
-            button_hot->SetHotTracked(true);
+          SetInitialHotTrackedView(to_select, direction);
           break;
         }
       }
@@ -2597,4 +2612,25 @@ void MenuController::HandleMouseLocation(SubmenuView* source,
   }
 }
 
+void MenuController::SetHotTrackedButton(CustomButton* hot_button,
+                                         bool is_hot_tracked) {
+  DCHECK(hot_button);

[sky, 2016/02/19 01:07:14]

What happens if hot_button is deleted while the menu is up?

[varkha, 2016/02/23 00:41:05]

You mean |hot_tracked_| (which can be passed in line 964 above). I have updated
ViewHierarchyChanged handler to watch for this and have also added a test for
this. I have tried deleting a button when some key is pressed while it is hot
and sure enough I can reproduce a crash unless we watch for it. Thanks!

+  hot_button->SetHotTracked(is_hot_tracked);
+  DCHECK(is_hot_tracked || (hot_button_ == hot_button));
+  hot_button_ = is_hot_tracked ? hot_button : nullptr;
+}
+
+void MenuController::SetInitialHotTrackedView(
+    MenuItemView* item,
+    SelectionIncrementDirectionType direction) {
+  if (!item)
+    return;
+  SetSelection(item, SELECTION_DEFAULT);
+  View* hot_view =
+      GetInitialFocusableView(item, direction == INCREMENT_SELECTION_DOWN);
+  CustomButton* hot_button = CustomButton::AsCustomButton(hot_view);
+  if (hot_button)
+    SetHotTrackedButton(hot_button, true);
+}
+
 }  // namespace views