Allow GrGLEffects to produce variable length keys.

src/gpu/effects/GrYUVtoRGBEffect.cpp

Index: src/gpu/effects/GrYUVtoRGBEffect.cpp
diff --git a/src/gpu/effects/GrYUVtoRGBEffect.cpp b/src/gpu/effects/GrYUVtoRGBEffect.cpp
index 76b85810c1210bb4a37784ea830d6b6389b923ad..15e51a2c625d06373cb14503f90cf27efcf0a386 100644
--- a/src/gpu/effects/GrYUVtoRGBEffect.cpp
+++ b/src/gpu/effects/GrYUVtoRGBEffect.cpp
@@ -37,7 +37,7 @@ public:
     class GLEffect : public GrGLEffect {
     public:
         // this class always generates the same code.
-        static EffectKey GenKey(const GrDrawEffect&, const GrGLCaps&) { return 0; }
+        static void GenKey(const GrDrawEffect&, const GrGLCaps&, GrEffectKeyBuilder*) {}
 
         GLEffect(const GrBackendEffectFactory& factory,
                  const GrDrawEffect&)
@@ -46,7 +46,7 @@ public:
 
         virtual void emitCode(GrGLShaderBuilder* builder,
                               const GrDrawEffect&,
-                              EffectKey,
+                              const GrEffectKey&,
                               const char* outputColor,
                               const char* inputColor,
                               const TransformedCoordsArray& coords,