Refactor tracking of bound vbufs and ibufs and vertex attrib arrays.
Review URL: https://codereview.appspot.com/7359045

git-svn-id: http://skia.googlecode.com/svn/trunk@7779 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/gl/GrGLProgram.h b/src/gpu/gl/GrGLProgram.h
index 2c3c973..2c48d73 100644
--- a/src/gpu/gl/GrGLProgram.h
+++ b/src/gpu/gl/GrGLProgram.h
@@ -81,11 +81,13 @@
     /**
      * Attribute indices. These should not overlap.
      */
-    static int PositionAttributeIdx() { return 0; }
-    static int ColorAttributeIdx() { return 1; }
-    static int CoverageAttributeIdx() { return 2; }
-    static int EdgeAttributeIdx() { return 3; }
-    static int TexCoordAttributeIdx() { return 4; }
+    enum {
+        kPositionAttributeIndex = 0,
+        kColorAttributeIndex = 1,
+        kCoverageAttributeIndex = 2,
+        kEdgeAttributeIndex = 3,
+        kTexCoordAttributeIndex = 4,
+    };
 
     /**
      * Some GL state that is relevant to programs is not stored per-program. In particular vertex