Make --enable-delegated-renderer show stuff on Mac

content/browser/renderer_host/render_widget_helper_mac.mm

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "content/browser/renderer_host/render_widget_helper.h"
+
+#import <Cocoa/Cocoa.h>
+
+#include "base/bind.h"
+#include "content/browser/gpu/gpu_process_host.h"
+#include "content/browser/gpu/gpu_surface_tracker.h"
+#include "content/common/gpu/gpu_messages.h"
+
+// Declare methods used to present swaps to this view.
+@interface NSView (ContentCompositingView)
+- (void)onNativeSurfaceBuffersSwappedWithParams:
+      (GpuHostMsg_AcceleratedSurfaceBuffersSwapped_Params)params;
+@end
+
+@implementation NSView (ContentCompositingView)
+- (void)onNativeSurfaceBuffersSwappedWithParams:
+      (GpuHostMsg_AcceleratedSurfaceBuffersSwapped_Params)params {
+}
+@end
+
+namespace {
+
+void OnNativeSurfaceBuffersSwappedOnUIThread(
+    const GpuHostMsg_AcceleratedSurfaceBuffersSwapped_Params& params) {
+  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
+  gfx::AcceleratedWidget native_widget =
+      content::GpuSurfaceTracker::Get()->AcquireNativeWidget(params.surface_id);
+  [native_widget onNativeSurfaceBuffersSwappedWithParams:params];
+}
+
+}  // namespace
+
+namespace content {
+
+void RenderWidgetHelper::OnNativeSurfaceBuffersSwappedOnIOThread(
+    GpuProcessHost* gpu_process_host,
+    const GpuHostMsg_AcceleratedSurfaceBuffersSwapped_Params& params) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+
+  // Immediately acknowledge this frame on the IO thread instead of the UI
+  // thread. The UI thread will wait on the GPU process. If the UI thread
+  // were to be responsible for acking swaps, then there would be a cycle
+  // and a potential deadlock.
+  // TODO(ccameron): This immediate ack circumvents GPU back-pressure that
+  // is necessary to throttle renderers. Fix that.
+  // TODO(ccameron): It is possible that the IOSurface will be deleted or
+  // reused soon as it is acked. Take out a reference to the IOSurface here,
+  // to ensure the IOSurface does not disappear before routing to the UI
+  // thread.
+  AcceleratedSurfaceMsg_BufferPresented_Params ack_params;
+  ack_params.sync_point = 0;
+  ack_params.renderer_id = 0;
+  gpu_process_host->Send(new AcceleratedSurfaceMsg_BufferPresented(
+      params.route_id, ack_params));
+
+  BrowserThread::PostTask(
+      BrowserThread::UI,
+      FROM_HERE,
+      base::Bind(&OnNativeSurfaceBuffersSwappedOnUIThread, params));
+}
+
+}  // namespace content