remove unneeded preroll

src/core/SkPictureShader.cpp

Index: src/core/SkPictureShader.cpp
diff --git a/src/core/SkPictureShader.cpp b/src/core/SkPictureShader.cpp
index adf2bb63a8bbdffe7c7e5a95f61c3088f66b20e4..cf0157c2a59fd880b4f9f3fe65bfd25a0b8e25cc 100644
--- a/src/core/SkPictureShader.cpp
+++ b/src/core/SkPictureShader.cpp
@@ -223,10 +223,6 @@ SkShader::Context* SkPictureShader::onCreateContext(const ContextRec& rec, void*
     return PictureShaderContext::Create(storage, *this, rec, bitmapShader);
 }
 
-void SkPictureShader::onPreroll() const {
-    fPicture->preroll(NULL, NULL, NULL, NULL);
-}
-
 /////////////////////////////////////////////////////////////////////////////////////////
 
 SkShader::Context* SkPictureShader::PictureShaderContext::Create(void* storage,