Bumped num stages to 4 in preparation for AA clipping

http://codereview.appspot.com/6135046/



git-svn-id: http://skia.googlecode.com/svn/trunk@3783 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/GrDrawState.h b/src/gpu/GrDrawState.h
index 270912e..63bc15a 100644
--- a/src/gpu/GrDrawState.h
+++ b/src/gpu/GrDrawState.h
@@ -38,7 +38,7 @@
      * or not.
      */
     enum {
-        kNumStages = 3,
+        kNumStages = 4,
         kMaxTexCoords = kNumStages
     };