Accept options in history APIs to allow scroll restoration to be disabled

public/platform/WebHistoryScrollRestorationType.h

Index: public/platform/WebHistoryScrollRestorationType.h
diff --git a/public/platform/WebImageGenerator.h b/public/platform/WebHistoryScrollRestorationType.h
similarity index 86%
copy from public/platform/WebImageGenerator.h
copy to public/platform/WebHistoryScrollRestorationType.h
index bb17f4d6df96a2dcc73efa069d2c6646a2338ab9..5f074041fcad3d49d58200fc5bcff515c2b4aa56 100644
--- a/public/platform/WebImageGenerator.h
+++ b/public/platform/WebHistoryScrollRestorationType.h
@@ -28,21 +28,16 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef WebImageGenerator_h
-#define WebImageGenerator_h
-
-#include "WebCommon.h"
-
-class SkData;
-class SkImageGenerator;
+#ifndef WebHistoryScrollRestorationType_h
+#define WebHistoryScrollRestorationType_h
 
 namespace blink {
 
-class BLINK_EXPORT WebImageGenerator {
-public:
-    static SkImageGenerator* create(SkData*);
+// Represents scroll restoration type for history item.
+enum WebHistoryScrollRestorationType {
+    WebHistoryScrollRestorationAuto,
+    WebHistoryScrollRestorationManual
 };
 
 } // namespace blink
-
 #endif