pathops: Add missing header guards in two files.

src/pathops/SkIntersectionHelper.h

Index: src/pathops/SkIntersectionHelper.h
diff --git a/src/pathops/SkIntersectionHelper.h b/src/pathops/SkIntersectionHelper.h
index 647b94b35f4f184cf701b1aa7a59335262b7cdef..9a8a582af64e7d2e537c5d2096ae5455adaaf8c0 100644
--- a/src/pathops/SkIntersectionHelper.h
+++ b/src/pathops/SkIntersectionHelper.h
@@ -4,6 +4,9 @@
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
+#ifndef SkIntersectionHelper_DEFINED
+#define SkIntersectionHelper_DEFINED
+
 #include "SkOpContour.h"
 #include "SkOpSegment.h"
 #include "SkPath.h"
@@ -106,3 +109,5 @@ public:
 private:
     SkOpSegment* fSegment;
 };
+
+#endif