Allow ui::Compositor to disable commits during tab-switch

content/browser/compositor/browser_compositor_view_mac.mm

Index: content/browser/compositor/browser_compositor_view_mac.mm
diff --git a/content/browser/compositor/browser_compositor_view_mac.mm b/content/browser/compositor/browser_compositor_view_mac.mm
index bc89df17b830926a08c9c1989a77310baddbe9d1..322183d0570ff20a19ef6871219263b4ee653609 100644
--- a/content/browser/compositor/browser_compositor_view_mac.mm
+++ b/content/browser/compositor/browser_compositor_view_mac.mm
@@ -46,10 +46,20 @@ BrowserCompositorMac::BrowserCompositorMac()
           accelerated_widget_mac_->accelerated_widget(),
           content::GetContextFactory(),
           RenderWidgetResizeHelper::Get()->task_runner()) {
+  compositor_.SetLocksWillTimeOut(false);
+  Suspend();
 }
 
 BrowserCompositorMac::~BrowserCompositorMac() {}
 
+void BrowserCompositorMac::Suspend() {
+  compositor_suspended_lock_ = compositor_.GetCompositorLock();
+}
+
+void BrowserCompositorMac::Unsuspend() {
+  compositor_suspended_lock_ = nullptr;
+}
+
 // static
 scoped_ptr<BrowserCompositorMac> BrowserCompositorMac::Create() {
   if (g_recyclable_browser_compositor.Get())