cc: Avoid extra flush calls to Skia GrContext

cc/output/gl_renderer.cc

Index: cc/output/gl_renderer.cc
diff --git a/cc/output/gl_renderer.cc b/cc/output/gl_renderer.cc
index 67382c0765fdbda850124277406ad9363786b6e4..90bb79616518c6e51a03126bd8220def1914a828 100644
--- a/cc/output/gl_renderer.cc
+++ b/cc/output/gl_renderer.cc
@@ -655,7 +655,7 @@ static skia::RefPtr<SkImage> ApplyImageFilter(
   surface->getCanvas()->translate(-dst_rect.x(), -dst_rect.y());
   surface->getCanvas()->drawImage(srcImage.get(), src_rect.x(), src_rect.y(),
                                   &paint);
-
+  surface->getCanvas()->flush();
   skia::RefPtr<SkImage> image = skia::AdoptRef(surface->newImageSnapshot());
   if (!image || !image->isTextureBacked()) {
     return skia::RefPtr<SkImage>();