When getGLInstance is called on a frag proc, the resulting GrGLFragmentProcessor will be the root of a tree of GrGLFragmentProcessors that mirrors the GrFragmentProcessor's tree. This allows setData() to be called recursively (removing the responsibility from compose shader) and allows gl instances direct access to their children gl instances so they can emit their code.

BUG=skia:4182

Review URL: https://codereview.chromium.org/1287023009
diff --git a/src/effects/gradients/SkGradientShader.cpp b/src/effects/gradients/SkGradientShader.cpp
index 763cef5..ebfa75f 100644
--- a/src/effects/gradients/SkGradientShader.cpp
+++ b/src/effects/gradients/SkGradientShader.cpp
@@ -940,7 +940,7 @@
                    a);
 }
 
-void GrGLGradientEffect::setData(const GrGLProgramDataManager& pdman,
+void GrGLGradientEffect::onSetData(const GrGLProgramDataManager& pdman,
                                  const GrProcessor& processor) {
 
     const GrGradientEffect& e = processor.cast<GrGradientEffect>();