Allow GrGLEffects to produce variable length keys.

R=robertphillips@google.com, jvanverth@google.com

Author: bsalomon@google.com

Review URL: https://codereview.chromium.org/385713005
diff --git a/src/gpu/gl/GrGLVertexEffect.h b/src/gpu/gl/GrGLVertexEffect.h
index 40b4b34..eba1fbe 100644
--- a/src/gpu/gl/GrGLVertexEffect.h
+++ b/src/gpu/gl/GrGLVertexEffect.h
@@ -26,7 +26,7 @@
      */
     virtual void emitCode(GrGLFullShaderBuilder* builder,
                           const GrDrawEffect& drawEffect,
-                          EffectKey key,
+                          const GrEffectKey& key,
                           const char* outputColor,
                           const char* inputColor,
                           const TransformedCoordsArray& coords,
@@ -37,7 +37,7 @@
      */
     virtual void emitCode(GrGLShaderBuilder* builder,
                           const GrDrawEffect& drawEffect,
-                          EffectKey key,
+                          const GrEffectKey& key,
                           const char* outputColor,
                           const char* inputColor,
                           const TransformedCoordsArray& coords,