Add some missing header include guards

src/gpu/GrAAConvexPathRenderer.h

Index: src/gpu/GrAAConvexPathRenderer.h
diff --git a/src/gpu/GrAAConvexPathRenderer.h b/src/gpu/GrAAConvexPathRenderer.h
index 62394a3a74bb98cc6b15fe09e7145643555c0d86..4dd858509e12767eb1cecb83e738d0ec5769f19d 100644
--- a/src/gpu/GrAAConvexPathRenderer.h
+++ b/src/gpu/GrAAConvexPathRenderer.h
@@ -6,8 +6,10 @@
  * found in the LICENSE file.
  */
 
-#include "GrPathRenderer.h"
+#ifndef GrAAConvexPathRenderer_DEFINED
+#define GrAAConvexPathRenderer_DEFINED
 
+#include "GrPathRenderer.h"
 
 class GrAAConvexPathRenderer : public GrPathRenderer {
 public:
@@ -24,3 +26,5 @@ protected:
                             GrDrawTarget* target,
                             bool antiAlias) SK_OVERRIDE;
 };
+
+#endif