Fixes a crash when InkDropDelegate gets destroyed after its InkDropHost

ui/views/controls/button/custom_button.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/views/controls/button/custom_button.h"
 
 #include "ui/accessibility/ax_view_state.h"
 #include "ui/events/event.h"
 #include "ui/events/event_utils.h"
 #include "ui/events/keycodes/keyboard_codes.h"
@@ skipping 38 matching lines @@
         !strcmp(classname, LabelButton::kViewClassName) ||
         !strcmp(classname, RadioButton::kViewClassName) ||
         !strcmp(classname, MenuButton::kViewClassName)) {
       return static_cast<CustomButton*>(view);
     }
   }
   return NULL;
 }
 
 CustomButton::~CustomButton() {
+  // InkDropDelegate needs to be destroyed by now since it may need to call
+  // methods on |this| via InkDropHost.
+  DCHECK(!ink_drop_delegate_);
 }
 
 void CustomButton::SetState(ButtonState state) {
   if (state == state_)
     return;
 
   if (animate_on_state_change_ &&
       (!is_throbbing_ || !hover_animation_->is_animating())) {
     is_throbbing_ = false;
     if ((state_ == STATE_HOVERED) && (state == STATE_NORMAL)) {
@@ skipping 262 matching lines @@
 ////////////////////////////////////////////////////////////////////////////////
 // CustomButton, protected:
 
 CustomButton::CustomButton(ButtonListener* listener)
     : Button(listener),
       state_(STATE_NORMAL),
       animate_on_state_change_(true),
       is_throbbing_(false),
       triggerable_event_flags_(ui::EF_LEFT_MOUSE_BUTTON),
       request_focus_on_press_(true),
+      ink_drop_delegate_(nullptr),
       notify_action_(NOTIFY_ON_RELEASE) {
   hover_animation_.reset(new gfx::ThrobAnimation(this));
   hover_animation_->SetSlideDuration(kHoverFadeDurationMs);
 }
 
 void CustomButton::StateChanged() {
 }
 
 bool CustomButton::IsTriggerableEvent(const ui::Event& event) {
   return event.type() == ui::ET_GESTURE_TAP_DOWN ||
@@ skipping 23 matching lines @@
         aura::client::GetCaptureClient(root_window);
     aura::Window* capture_window =
         capture_client ? capture_client->GetGlobalCaptureWindow() : nullptr;
     check_mouse_position = !capture_window || capture_window == root_window;
   }
 #endif
 
   return check_mouse_position && IsMouseHovered();
 }
 
-void CustomButton::SetInkDropDelegate(
-    scoped_ptr<InkDropDelegate> ink_drop_delegate) {
-  ink_drop_delegate_ = ink_drop_delegate.Pass();
-}
-
 ////////////////////////////////////////////////////////////////////////////////
 // CustomButton, View overrides (protected):
 
 void CustomButton::OnBoundsChanged(const gfx::Rect& previous_bounds) {
   Button::OnBoundsChanged(previous_bounds);
   if (ink_drop_delegate_)
     ink_drop_delegate_->OnLayout();
 }
 
 void CustomButton::ViewHierarchyChanged(
@@ skipping 11 matching lines @@
   return GetWidget() && GetWidget()->GetTopLevelWidget() != GetWidget();
 }
 
 bool CustomButton::FocusInChildWidget() const {
   return GetWidget() &&
          GetWidget()->GetRootView()->Contains(
              GetFocusManager()->GetFocusedView());
 }
 
 }  // namespace views