Fixes ink drop being "stuck" on when losing focus.

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/base/material_design/material_design_controller.h"
 #include "ui/events/event.h"
 #include "ui/events/event_utils.h"
@@ skipping 223 matching lines @@
   } else if (event.key_code() == ui::VKEY_RETURN) {
     SetState(STATE_NORMAL);
     NotifyClick(event);
   } else {
     return false;
   }
   return true;
 }
 
 bool CustomButton::OnKeyReleased(const ui::KeyEvent& event) {
-  if ((state_ == STATE_DISABLED) || (event.key_code() != ui::VKEY_SPACE))
-    return false;
-
-  SetState(STATE_NORMAL);
-  NotifyClick(event);
-  return true;
+  if ((state_ == STATE_PRESSED) && (event.key_code() == ui::VKEY_SPACE)) {
+    SetState(STATE_NORMAL);
+    NotifyClick(event);
+    return true;
+  }
+  return false;
 }
 
 void CustomButton::OnGestureEvent(ui::GestureEvent* event) {
   if (state_ == STATE_DISABLED) {
     Button::OnGestureEvent(event);
     return;
   }
 
   if (event->type() == ui::ET_GESTURE_TAP && IsTriggerableEvent(*event)) {
     // Set the button state to hot and start the animation fully faded in. The
@@ skipping 104 matching lines @@
 // CustomButton, View overrides (public):
 
 void CustomButton::ViewHierarchyChanged(
     const ViewHierarchyChangedDetails& details) {
   if (!details.is_add && state_ != STATE_DISABLED)
     SetState(STATE_NORMAL);
 }
 
 void CustomButton::OnBlur() {
   Button::OnBlur();
-  if (IsHotTracked())
+  if (IsHotTracked() || state_ == STATE_PRESSED) {

[bruthig, 2016/05/31 14:20:40]

This opens up the following edge case:

1. Press and hold left mouse button
2. Obtain keyboard focus (still holding left mouse down)
3. Lose keyboard focus (i.e. OnBlur() is called)
4. Release left mouse button (which presumably triggers the button action)

I believe at step 4 there will be no visual indication that the button is armed
and firing an action due to the mouse release may catch a user off guard. 
Although it appears as though this was also a problem pre-MD however so I'm not
sure which is the lesser of two evils.

Would it be possible to 'unarm' the button for mouse and keyboard when OnBlur()
is called?  And would this make sense?  And if we go that far, we should also be
considering gesture events too.

sky@, what are your thoughts on this?

[bruthig, 2016/05/31 14:23:42]

At the very least I do believe this change is an improvement as it prevents the
ripple from getting stuck on.  But we should at the very least create an issue
or a TODO to make buttons work more robustly between the three different input
methods.

     SetState(STATE_NORMAL);
+    if (ink_drop_delegate())
+      ink_drop_delegate()->OnAction(views::InkDropState::HIDDEN);
+  }
 }
 
 bool CustomButton::ShouldShowInkDropForFocus() const {
   return true;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // CustomButton, protected:
 
 CustomButton::CustomButton(ButtonListener* listener)
@@ skipping 64 matching lines @@
   Button::NotifyClick(event);
 }
 
 void CustomButton::OnClickCanceled(const ui::Event& event) {
   if (ink_drop_delegate())
     ink_drop_delegate()->OnAction(views::InkDropState::HIDDEN);
   Button::OnClickCanceled(event);
 }
 
 }  // namespace views