Rename SkInsetConvexPolygon to SkOffsetPolygon.

Prep for adding new offset routines.

Change-Id: I261c22d9998e5ae4567b697c5f20a31f20777ac1
Reviewed-on: https://skia-review.googlesource.com/116800
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Jim Van Verth <jvanverth@google.com>
diff --git a/src/utils/SkShadowTessellator.cpp b/src/utils/SkShadowTessellator.cpp
index 8815ce6..75e4059 100755
--- a/src/utils/SkShadowTessellator.cpp
+++ b/src/utils/SkShadowTessellator.cpp
@@ -9,7 +9,7 @@
 #include "SkColorData.h"
 #include "SkDrawShadowInfo.h"
 #include "SkGeometry.h"
-#include "SkInsetConvexPolygon.h"
+#include "SkOffsetPolygon.h"
 #include "SkPath.h"
 #include "SkPoint3.h"
 #include "SkPointPriv.h"