Adding missing include guard to ui/views/animation/ink_drop_stub.h

Change-Id: Id3e0139beeca89444f4100de67c21da579c49047
Reviewed-on: https://chromium-review.googlesource.com/684739Reviewed-by: Mohsen Izadi <mohsen@chromium.org>
Commit-Queue: Daniel Bratell <bratell@opera.com>
Cr-Commit-Position: refs/heads/master@{#504388}

ui/views/animation/ink_drop_stub.h

@@ -2,6 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#ifndef UI_VIEWS_ANIMATION_INK_DROP_STUB_H_
+#define UI_VIEWS_ANIMATION_INK_DROP_STUB_H_
+
 #include "base/macros.h"
 #include "ui/views/animation/ink_drop.h"
 #include "ui/views/views_export.h"
@@ -31,3 +34,5 @@ class VIEWS_EXPORT InkDropStub : public InkDrop {
 };
 
 }  // namespace views
+
+#endif  // UI_VIEWS_ANIMATION_INK_DROP_STUB_H_