Don't clear in SkSurface::NewWrappedRenderTarget

src/image/SkSurface_Gpu.cpp

Index: src/image/SkSurface_Gpu.cpp
diff --git a/src/image/SkSurface_Gpu.cpp b/src/image/SkSurface_Gpu.cpp
index ff18a04754b4f489c3e30e7e6fc023db50a0a451..20fcbf333e52ba7e050f780807a919131b327f44 100644
--- a/src/image/SkSurface_Gpu.cpp
+++ b/src/image/SkSurface_Gpu.cpp
@@ -113,8 +113,7 @@ SkSurface* SkSurface::NewWrappedRenderTarget(GrContext* context, GrBackendTextur
     if (!surface) {
         return NULL;
     }
-    SkAutoTUnref<SkGpuDevice> device(SkGpuDevice::Create(surface->asRenderTarget(), props,
-                                                         SkGpuDevice::kNeedClear_Flag));
+    SkAutoTUnref<SkGpuDevice> device(SkGpuDevice::Create(surface->asRenderTarget(), props));
     if (!device) {
         return NULL;
     }