Fix views compilation on Linux with toolkit_views=1.

ui/views/bubble/bubble_delegate.h

Index: ui/views/bubble/bubble_delegate.h
diff --git a/ui/views/bubble/bubble_delegate.h b/ui/views/bubble/bubble_delegate.h
index 81fd9c84208953e86de88ff9de7e58f46fe5fc80..c7f55642650da135c857cf932c62f69219c8d820 100644
--- a/ui/views/bubble/bubble_delegate.h
+++ b/ui/views/bubble/bubble_delegate.h
@@ -72,8 +72,8 @@ class VIEWS_EXPORT BubbleDelegateView : public WidgetDelegateView,
   int margin() const { return margin_; }
   void set_margin(int margin) { margin_ = margin; }
 
-  gfx::NativeWindow parent_window() const { return parent_window_; }
-  void set_parent_window(gfx::NativeWindow window) { parent_window_ = window; }
+  gfx::NativeView parent_window() const { return parent_window_; }
+  void set_parent_window(gfx::NativeView window) { parent_window_ = window; }
 
   bool use_focusless() const { return use_focusless_; }
   void set_use_focusless(bool use_focusless) {
@@ -156,7 +156,7 @@ class VIEWS_EXPORT BubbleDelegateView : public WidgetDelegateView,
   bool use_focusless_;
 
   // Parent native window of the bubble.
-  gfx::NativeWindow parent_window_;
+  gfx::NativeView parent_window_;
 
   DISALLOW_COPY_AND_ASSIGN(BubbleDelegateView);
 };