Move BackgroundBleedAvoidance definition to a separate file.

third_party/WebKit/Source/core/layout/BackgroundBleedAvoidance.h

Index: third_party/WebKit/Source/core/layout/BackgroundBleedAvoidance.h
diff --git a/third_party/WebKit/Source/core/layout/BackgroundBleedAvoidance.h b/third_party/WebKit/Source/core/layout/BackgroundBleedAvoidance.h
new file mode 100644
index 0000000000000000000000000000000000000000..d86389b67eb3eb04335adae2062f3ce9903424f3
--- /dev/null
+++ b/third_party/WebKit/Source/core/layout/BackgroundBleedAvoidance.h
@@ -0,0 +1,15 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef BackgroundBleedAvoidance_h
+#define BackgroundBleedAvoidance_h
+
+enum BackgroundBleedAvoidance {
+    BackgroundBleedNone,
+    BackgroundBleedShrinkBackground,
+    BackgroundBleedClipOnly,
+    BackgroundBleedClipLayer,
+};
+
+#endif // BackgroundBleedAvoidance_h