views: implement width snapping for DialogDelegateViews

ui/views/bubble/tray_bubble_view.h

 // 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.
 
 #ifndef UI_VIEWS_BUBBLE_TRAY_BUBBLE_VIEW_H_
 #define UI_VIEWS_BUBBLE_TRAY_BUBBLE_VIEW_H_
 
 #include <memory>
 
 #include "base/macros.h"
@@ skipping 113 matching lines @@
   views::NonClientFrameView* CreateNonClientFrameView(
       views::Widget* widget) override;
   bool WidgetHasHitTestMask() const override;
   void GetWidgetHitTestMask(gfx::Path* mask) const override;
   base::string16 GetAccessibleWindowTitle() const override;
 
   // Overridden from views::BubbleDialogDelegateView.
   void OnBeforeBubbleWidgetInit(Widget::InitParams* params,
                                 Widget* bubble_widget) const override;
 
+  // Overridden from views::DialogDelegateView.

[Peter Kasting, 2017/03/30 00:35:36]

Nit: Combine this and below list into the one above

+  gfx::Size GetUnsnappedPreferredSize() const override;
+
   // Overridden from views::View.
-  gfx::Size GetPreferredSize() const override;
   gfx::Size GetMaximumSize() const override;
   int GetHeightForWidth(int width) const override;
   void OnMouseEntered(const ui::MouseEvent& event) override;
   void OnMouseExited(const ui::MouseEvent& event) override;
   void GetAccessibleNodeData(ui::AXNodeData* node_data) override;
 
   // Overridden from MouseWatcherListener
   void MouseMovedOutOfHost() override;
 
  protected:
@@ skipping 27 matching lines @@
 
   // Used to find any mouse movements.
   std::unique_ptr<MouseWatcher> mouse_watcher_;
 
   DISALLOW_COPY_AND_ASSIGN(TrayBubbleView);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_BUBBLE_TRAY_BUBBLE_VIEW_H_