views: implement width snapping for DialogDelegateViews

ui/views/widget/root_view_unittest.cc

Index: ui/views/widget/root_view_unittest.cc
diff --git a/ui/views/widget/root_view_unittest.cc b/ui/views/widget/root_view_unittest.cc
index 54eeee2164465677ba5b43a9869d72fb1d715e13..e588771c012ac390348e852069043f95f2215fc6 100644
--- a/ui/views/widget/root_view_unittest.cc
+++ b/ui/views/widget/root_view_unittest.cc
@@ -549,7 +549,9 @@ class RootViewTestDialogDelegate : public DialogDelegateView {
   int layout_count() const { return layout_count_; }
 
   // DialogDelegateView:
-  gfx::Size GetPreferredSize() const override { return preferred_size_; }
+  gfx::Size GetUnsnappedPreferredSize() const override {
+    return preferred_size_;
+  }
   void Layout() override {
     EXPECT_EQ(size(), preferred_size_);
     ++layout_count_;