Update ConstrainedWindowViews appearance according to mock

ui/views/controls/message_box_view.h

Index: ui/views/controls/message_box_view.h
diff --git a/ui/views/controls/message_box_view.h b/ui/views/controls/message_box_view.h
index 249182aa4a8af34a405e12e6cb649cc8950c3014..b431a9dc516bc4469151a2d7f2b4b8d449b5a9de 100644
--- a/ui/views/controls/message_box_view.h
+++ b/ui/views/controls/message_box_view.h
@@ -47,6 +47,11 @@ class VIEWS_EXPORT MessageBoxView : public View {
     string16 message;
     string16 default_prompt;
     int message_width;
+    int top_inset;
+    int bottom_inset;
+    int left_inset;
+    int right_inset;
+    int inter_row_vertical_spacing;
   };
 
   explicit MessageBoxView(const InitParams& params);
@@ -110,6 +115,15 @@ class VIEWS_EXPORT MessageBoxView : public View {
   // Maximum width of the message label.
   int message_width_;
 
+  // Insets for the grid layout.
+  int top_inset_;
+  int bottom_inset_;
+  int left_inset_;
+  int right_inset_;
+
+  // Spacing between rows in the grid layout.
+  int inter_row_vertical_spacing_;
+
   DISALLOW_COPY_AND_ASSIGN(MessageBoxView);
 };