Fix RHWVChildFrame::CopyFromSurface

Currently this method earlies out and returns an empty SkBitmap if
OOP-D is enabled. It should just proceed the same way as the
non-OOP-D case.

Bug: 903453
Change-Id: I0943279e2d98885682f5b8d4e619413293575b5a
Reviewed-on: https://chromium-review.googlesource.com/c/1327418Reviewed-by: Fady Samuel <fsamuel@chromium.org>
Commit-Queue: Saman Sami <samans@chromium.org>
Cr-Commit-Position: refs/heads/master@{#606637}

content/browser/renderer_host/render_widget_host_view_child_frame.cc

@@ -869,12 +869,6 @@ void RenderWidgetHostViewChildFrame::CopyFromSurface(
     const gfx::Rect& src_subrect,
     const gfx::Size& output_size,
     base::OnceCallback<void(const SkBitmap&)> callback) {
-  // TODO(crbug.com/812059): Need a "copy from surface" VIZ API.
-  if (enable_viz_) {
-    std::move(callback).Run(SkBitmap());
-    return;
-  }
-
   if (!IsSurfaceAvailableForCopy()) {
     // Defer submitting the copy request until after a frame is drawn, at which
     // point we should be guaranteed that the surface is available.