Move LayerHitTestRects to a separate file.

third_party/WebKit/Source/core/paint/LayerHitTestRects.h

Index: third_party/WebKit/Source/core/paint/LayerHitTestRects.h
diff --git a/third_party/WebKit/Source/core/paint/LayerHitTestRects.h b/third_party/WebKit/Source/core/paint/LayerHitTestRects.h
new file mode 100644
index 0000000000000000000000000000000000000000..65aaf2331e390b59c1e732afab9e6ae1c2056b41
--- /dev/null
+++ b/third_party/WebKit/Source/core/paint/LayerHitTestRects.h
@@ -0,0 +1,20 @@
+// 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 LayerHitTestRects_h
+#define LayerHitTestRects_h
+
+#include "platform/geometry/LayoutRect.h"
+#include "wtf/HashMap.h"
+#include "wtf/Vector.h"
+
+namespace blink {
+
+class PaintLayer;
+
+typedef WTF::HashMap<const PaintLayer*, Vector<LayoutRect>> LayerHitTestRects;
+
+}  // namespace blink
+
+#endif  // LayerHitTestRects_h