Mac: Fix bad framerate when capturing tab

content/browser/compositor/browser_compositor_view_private_mac.mm

Index: content/browser/compositor/browser_compositor_view_private_mac.mm
diff --git a/content/browser/compositor/browser_compositor_view_private_mac.mm b/content/browser/compositor/browser_compositor_view_private_mac.mm
index a6ce4c2c664ba28cfe92164d4bb5159f975e8e5d..cc70017e5661e458bb74d34b39a8efee527282bb 100644
--- a/content/browser/compositor/browser_compositor_view_private_mac.mm
+++ b/content/browser/compositor/browser_compositor_view_private_mac.mm
@@ -196,6 +196,15 @@ void BrowserCompositorViewMacInternal::GotSoftwareFrame(
   }
 }
 
+bool BrowserCompositorViewMacInternal::AcceleratedLayerShouldAckImmediately()
+    const {
+  // If there is no client then the accelerated layer is not in the hierarchy
+  // and will never draw.
+  if (!client_)
+    return true;
+  return client_->BrowserCompositorViewShouldAckImmediately();
+}
+
 void BrowserCompositorViewMacInternal::AcceleratedLayerDidDrawFrame(
     bool succeeded) {
   if (accelerated_layer_output_surface_id_) {