don't leak the bitmapShader

src/core/SkPictureShader.cpp

Index: src/core/SkPictureShader.cpp
diff --git a/src/core/SkPictureShader.cpp b/src/core/SkPictureShader.cpp
index 9555624ffe3ff3a1a2d84e92ab1696dfb1348813..290baa828473be8fb853e8561a99eadf13a776df 100644
--- a/src/core/SkPictureShader.cpp
+++ b/src/core/SkPictureShader.cpp
@@ -119,7 +119,7 @@ SkShader::Context* SkPictureShader::onCreateContext(const ContextRec& rec, void*
     if (NULL == bitmapShader.get()) {
         return NULL;
     }
-    return PictureShaderContext::Create(storage, *this, rec, bitmapShader.detach());
+    return PictureShaderContext::Create(storage, *this, rec, bitmapShader);
 }
 
 /////////////////////////////////////////////////////////////////////////////////////////