Mac: Fix bad framerate when capturing tab

content/browser/compositor/browser_compositor_view_mac.h

Index: content/browser/compositor/browser_compositor_view_mac.h
diff --git a/content/browser/compositor/browser_compositor_view_mac.h b/content/browser/compositor/browser_compositor_view_mac.h
index f92945fcb5db8d6a160883ca9c5a43ec77fe89a0..c9a1fb9f5bc2c66319774feb2fb08e020133f12d 100644
--- a/content/browser/compositor/browser_compositor_view_mac.h
+++ b/content/browser/compositor/browser_compositor_view_mac.h
@@ -41,6 +41,10 @@ class BrowserCompositorViewMacInternal;
 // NSView backed by a ui::Compositor).
 class BrowserCompositorViewMacClient {
  public:
+  // Drawing is usually throttled by the rate at which CoreAnimation draws
+  // frames to the screen. This can be used to disable throttling.
+  virtual bool BrowserCompositorViewShouldAckImmediately() const = 0;
+
   // Called when a frame is drawn, and used to pass latency info back to the
   // renderer (if any).
   virtual void BrowserCompositorViewFrameSwapped(