Increase bits for effect attribute key

include/gpu/GrBackendEffectFactory.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrBackendEffectFactory_DEFINED
 #define GrBackendEffectFactory_DEFINED
 
@@ skipping 23 matching lines @@
     enum {
         kNoEffectKey = 0,
         kEffectKeyBits = 12,
         /**
          * Some aspects of the generated code may be determined by the particular textures that are
          * associated with the effect. These manipulations are performed by GrGLShaderBuilder beyond
          * GrGLEffects' control. So there is a dedicated part of the key which is combined
          * automatically with the bits produced by GrGLEffect::GenKey().
          */
         kTextureKeyBits = 6,
-        kAttribKeyBits = 4
+        kAttribKeyBits = 6
     };
 
     virtual EffectKey glEffectKey(const GrEffectStage&, const GrGLCaps&) const = 0;
     virtual GrGLEffect* createGLInstance(const GrEffectRef&) const = 0;
 
     bool operator ==(const GrBackendEffectFactory& b) const {
         return fEffectClassID == b.fEffectClassID;
     }
     bool operator !=(const GrBackendEffectFactory& b) const {
         return !(*this == b);
@@ skipping 23 matching lines @@
         return static_cast<EffectKey>(id);
     }
 
     EffectKey fEffectClassID;
 
 private:
     static int32_t fCurrEffectClassID;
 };
 
 #endif