Increase bits for effect attribute key. 

We can have an attribute index value up to 7, but only allow 2 bits for each
index in GrGLEffect::GenAttribKey. This change gives them 3 bits (and fixes an
assert when running tests in debug).

Review URL: https://codereview.chromium.org/12431018/


git-svn-id: http://skia.googlecode.com/svn/trunk@8140 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/include/gpu/GrBackendEffectFactory.h b/include/gpu/GrBackendEffectFactory.h
index f5e638f..99d6a73 100644
--- a/include/gpu/GrBackendEffectFactory.h
+++ b/include/gpu/GrBackendEffectFactory.h
@@ -41,7 +41,7 @@
          * automatically with the bits produced by GrGLEffect::GenKey().
          */
         kTextureKeyBits = 6,
-        kAttribKeyBits = 4
+        kAttribKeyBits = 6
     };
 
     virtual EffectKey glEffectKey(const GrEffectStage&, const GrGLCaps&) const = 0;