views: implement width snapping for DialogDelegateViews

ui/views/window/dialog_delegate_unittest.cc

Index: ui/views/window/dialog_delegate_unittest.cc
diff --git a/ui/views/window/dialog_delegate_unittest.cc b/ui/views/window/dialog_delegate_unittest.cc
index d11cfddde8f6aabf0595da8212e837a7e92e24b4..0d7b7ed411fb84235aba288cd38843f9544000dd 100644
--- a/ui/views/window/dialog_delegate_unittest.cc
+++ b/ui/views/window/dialog_delegate_unittest.cc
@@ -67,7 +67,9 @@ class TestDialog : public DialogDelegateView {
   }
 
   // DialogDelegateView overrides:
-  gfx::Size GetPreferredSize() const override { return gfx::Size(200, 200); }
+  gfx::Size GetUnsnappedPreferredSize() const override {
+    return gfx::Size(200, 200);
+  }
   bool AcceleratorPressed(const ui::Accelerator& accelerator) override {
     return should_handle_escape_;
   }