Mac ÜC: Enable back-pressure for the browser compositor

content/browser/compositor/browser_compositor_view_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/compositor/browser_compositor_view_mac.h"
 
 #include "base/debug/trace_event.h"
 #include "base/mac/scoped_cftyperef.h"
+#include "content/browser/compositor/gpu_process_transport_factory.h"
 #include "content/browser/renderer_host/compositing_iosurface_context_mac.h"
 #include "content/browser/renderer_host/compositing_iosurface_mac.h"
 #include "content/browser/renderer_host/software_layer_mac.h"
 #include "content/public/browser/context_factory.h"
 #include "ui/base/cocoa/animation_utils.h"
 #include "ui/gl/scoped_cgl.h"
 
 @interface BrowserCompositorViewMac (Private)
 - (void)layerDidDrawFrame;
 - (void)gotAcceleratedLayerError;
@@ skipping 22 matching lines @@
 };
 
 }  // namespace content
 
 
 // The default implementation of additions to the NSView interface for browser
 // compositing should never be called. Log an error if they are.
 @implementation NSView (BrowserCompositorView)
 
 - (void)gotAcceleratedIOSurfaceFrame:(uint64)surface_handle
+                 withOutputSurfaceID:(int)surface_id
                        withPixelSize:(gfx::Size)pixel_size
                      withScaleFactor:(float)scale_factor {
   DLOG(ERROR) << "-[NSView gotAcceleratedIOSurfaceFrame] called on "
               << "non-overriden class.";
 }
 
 - (void)gotSoftwareFrame:(cc::SoftwareFrameData*)frame_data
          withScaleFactor:(float)scale_factor
               withCanvas:(SkCanvas*)canvas {
   DLOG(ERROR) << "-[NSView gotSoftwareFrame] called on non-overridden class.";
 }
 
 @end  // NSView (BrowserCompositorView)
 
 @implementation BrowserCompositorViewMac : NSView
 
 - (id)initWithSuperview:(NSView*)view {
   if (self = [super init]) {
+    accelerated_layer_output_surface_id_ = 0;
     helper_.reset(new content::BrowserCompositorViewMacHelper(self));
 
     // Disable the fade-in animation as the layer and view are added.
     ScopedCAActionDisabler disabler;
 
     // Make this view host a transparent layer.
     background_layer_.reset([[CALayer alloc] init]);
     [background_layer_ setContentsGravity:kCAGravityTopLeft];
     [self setLayer:background_layer_];
     [self setWantsLayer:YES];
@@ skipping 60 matching lines @@
 
 - (void)resetClient {
   [accelerated_layer_ resetClient];
 }
 
 - (ui::Compositor*)compositor {
   return compositor_.get();
 }
 
 - (void)gotAcceleratedIOSurfaceFrame:(uint64)surface_handle
+                 withOutputSurfaceID:(int)surface_id
                        withPixelSize:(gfx::Size)pixel_size
                      withScaleFactor:(float)scale_factor {
+  DCHECK(!accelerated_layer_output_surface_id_);
+  accelerated_layer_output_surface_id_ = surface_id;
+
   ScopedCAActionDisabler disabler;
 
   // If there is already an accelerated layer, but it has the wrong scale
   // factor or it was poisoned, remove the old layer and replace it.
   base::scoped_nsobject<CompositingIOSurfaceLayer> old_accelerated_layer;
   if (accelerated_layer_ && (
           [accelerated_layer_ context]->HasBeenPoisoned() ||
           [accelerated_layer_ iosurface]->scale_factor() != scale_factor)) {
     old_accelerated_layer = accelerated_layer_;
     accelerated_layer_.reset();
@@ skipping 70 matching lines @@
 
   // This call can be nested insider ui::Compositor commit calls, and can also
   // make additional ui::Compositor commit calls. Avoid the potential recursion
   // by acknowledging the frame asynchronously.
   [self performSelector:@selector(layerDidDrawFrame)
              withObject:nil
              afterDelay:0];
 }
 
 - (void)layerDidDrawFrame {
+  if (!accelerated_layer_output_surface_id_)
+    return;
+
+  content::ImageTransportFactory::GetInstance()->OnSurfaceDisplayed(
+      accelerated_layer_output_surface_id_);
+  accelerated_layer_output_surface_id_ = 0;
 }
 
 @end  // BrowserCompositorViewMac