views: implement width snapping for DialogDelegateViews

ui/views/window/dialog_delegate.h

Index: ui/views/window/dialog_delegate.h
diff --git a/ui/views/window/dialog_delegate.h b/ui/views/window/dialog_delegate.h
index 6a11e65bab68208995be4982a5df06165411a9b7..afc6c758f1d34902cd61d5391f1afe6ec0cbe623 100644
--- a/ui/views/window/dialog_delegate.h
+++ b/ui/views/window/dialog_delegate.h
@@ -138,6 +138,8 @@ class VIEWS_EXPORT DialogDelegateView : public DialogDelegate,
   DialogDelegateView();
   ~DialogDelegateView() override;
 
+  virtual gfx::Size GetUnsnappedPreferredSize() const;

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

Nit: Comment

+
   // Overridden from DialogDelegate:
   void DeleteDelegate() override;
   Widget* GetWidget() override;
@@ -146,6 +148,7 @@ class VIEWS_EXPORT DialogDelegateView : public DialogDelegate,
 
   // Overridden from View:
   void GetAccessibleNodeData(ui::AXNodeData* node_data) override;
+  gfx::Size GetPreferredSize() const final;
   void ViewHierarchyChanged(
       const ViewHierarchyChangedDetails& details) override;