[content] Forward BeginFrameAcks through RWHVMac/BrowserCompositorMac.

content/browser/renderer_host/browser_compositor_view_mac.mm

Index: content/browser/renderer_host/browser_compositor_view_mac.mm
diff --git a/content/browser/renderer_host/browser_compositor_view_mac.mm b/content/browser/renderer_host/browser_compositor_view_mac.mm
index 7f2a79beee46d77d54e7f68b79ba31facdc8d2c3..d76f0a192b9661d02ef2183b548b328e6fb2942d 100644
--- a/content/browser/renderer_host/browser_compositor_view_mac.mm
+++ b/content/browser/renderer_host/browser_compositor_view_mac.mm
@@ -282,8 +282,17 @@ void BrowserCompositorMac::SwapCompositorFrame(
     recyclable_compositor_->compositor()->SetScaleAndSize(scale_factor,
                                                           pixel_size);
   }
+  cc::BeginFrameAck ack(frame.metadata.begin_frame_ack);
   delegated_frame_host_->SwapDelegatedFrame(compositor_frame_sink_id,
                                             local_surface_id, std::move(frame));
+  if (begin_frame_source_)
+    begin_frame_source_->DidFinishFrame(this, ack);
+}
+
+void BrowserCompositorMac::OnBeginFrameDidNotSwap(
+    const cc::BeginFrameAck& ack) {
+  if (begin_frame_source_)
+    begin_frame_source_->DidFinishFrame(this, ack);
 }
 
 void BrowserCompositorMac::SetHasTransparentBackground(bool transparent) {