Allow GrGLEffects to produce variable length keys.

src/effects/gradients/SkLinearGradient.cpp

Index: src/effects/gradients/SkLinearGradient.cpp
diff --git a/src/effects/gradients/SkLinearGradient.cpp b/src/effects/gradients/SkLinearGradient.cpp
index 332c9b4af92e5717f8ec5d8d24f2c5fc5ef9eeb6..9de459125a7639dd85404df19e1c55dea4f1679f 100644
--- a/src/effects/gradients/SkLinearGradient.cpp
+++ b/src/effects/gradients/SkLinearGradient.cpp
@@ -461,14 +461,14 @@ public:
 
     virtual void emitCode(GrGLShaderBuilder*,
                           const GrDrawEffect&,
-                          EffectKey,
+                          const GrEffectKey&,
                           const char* outputColor,
                           const char* inputColor,
                           const TransformedCoordsArray&,
                           const TextureSamplerArray&) SK_OVERRIDE;
 
-    static EffectKey GenKey(const GrDrawEffect& drawEffect, const GrGLCaps&) {
-        return GenBaseGradientKey(drawEffect);
+    static void GenKey(const GrDrawEffect& drawEffect, const GrGLCaps&, GrEffectKeyBuilder* b) {
+        b->add32(GenBaseGradientKey(drawEffect));
     }
 
 private:
@@ -538,15 +538,16 @@ GrEffect* GrLinearGradient::TestCreate(SkRandom* random,
 
 void GrGLLinearGradient::emitCode(GrGLShaderBuilder* builder,
                                   const GrDrawEffect&,
-                                  EffectKey key,
+                                  const GrEffectKey& key,
                                   const char* outputColor,
                                   const char* inputColor,
                                   const TransformedCoordsArray& coords,
                                   const TextureSamplerArray& samplers) {
-    this->emitUniforms(builder, key);
+    uint32_t baseKey = key.get32(0);
+    this->emitUniforms(builder, baseKey);
     SkString t = builder->ensureFSCoords2D(coords, 0);
     t.append(".x");
-    this->emitColor(builder, t.c_str(), key, outputColor, inputColor, samplers);
+    this->emitColor(builder, t.c_str(), baseKey, outputColor, inputColor, samplers);
 }
 
 /////////////////////////////////////////////////////////////////////