fix header file location.
source: https://bugs.webkit.org/show_bug.cgi?id=176983

--- Source/WebCore/platform/graphics/cairo/BackingStoreBackendCairoImpl.h.ORIG
+++ Source/WebCore/platform/graphics/cairo/BackingStoreBackendCairoImpl.h
@@ -20,7 +20,7 @@ 
 
 #if USE(CAIRO)
 #include "BackingStoreBackendCairo.h"
-#include <WebCore/HysteresisActivity.h>
+#include <WebCore/platform/HysteresisActivity.h>
 
 namespace WebCore {