Mac ÜC: Fix white page hangs

content/browser/compositor/browser_compositor_view_private_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_private_mac.h"
 
 #include "base/debug/trace_event.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 CompositingIOSurfaceLayer(Private)
+- (void)immediatelyForceDisplayAndAck;
+@end
+
 ////////////////////////////////////////////////////////////////////////////////
 // BrowserCompositorViewCocoa
 
 @implementation BrowserCompositorViewCocoa : NSView
 
 - (id)init {
   if (self = [super init]) {
     accelerated_layer_output_surface_id_ = 0;
     client_ = NULL;
     helper_.reset(new content::BrowserCompositorViewCocoaHelper(self));
@@ skipping 65 matching lines @@
 - (void)gotAcceleratedIOSurfaceFrame:(IOSurfaceID)surface_handle
                  withOutputSurfaceID:(int)surface_id
                      withLatencyInfo:(std::vector<ui::LatencyInfo>) latency_info
                        withPixelSize:(gfx::Size)pixel_size
                      withScaleFactor:(float)scale_factor {
   DCHECK(!accelerated_layer_output_surface_id_);
   accelerated_layer_output_surface_id_ = surface_id;
   accelerated_latency_info_.insert(accelerated_latency_info_.end(),
                                    latency_info.begin(), latency_info.end());
 
+  // If the client that wanted to display this frame has disappeared, don't
+  // bother creating the layers, just un-block the compositor and quit.
+  if (!client_) {
+    [self layerDidDrawFrame];
+    return;
+  }
+
   // Disable the fade-in animation as the layer is added, removed, or resized.
   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_;
@@ skipping 18 matching lines @@
     result = [accelerated_layer_ iosurface]->SetIOSurfaceWithContextCurrent(
         [accelerated_layer_ context], surface_handle, pixel_size, scale_factor);
     if (!result)
       LOG(ERROR) << "Failed SetIOSurface on CompositingIOSurfaceMac";
   }
   [accelerated_layer_ gotNewFrame];
 
   // Set the bounds of the accelerated layer to match the size of the frame.
   // If the bounds changed, force the content to be displayed immediately.
   CGRect new_layer_bounds = CGRectMake(
-    0,
-    0,
-    [accelerated_layer_ iosurface]->dip_io_surface_size().width(),
-    [accelerated_layer_ iosurface]->dip_io_surface_size().height());
+      0,
+      0,
+      [accelerated_layer_ iosurface]->dip_io_surface_size().width(),
+      [accelerated_layer_ iosurface]->dip_io_surface_size().height());
   bool bounds_changed = !CGRectEqualToRect(
       new_layer_bounds, [accelerated_layer_ bounds]);
   [accelerated_layer_ setBounds:new_layer_bounds];
   if (bounds_changed ||
       (client_ && client_->BrowserCompositorShouldDrawImmediately())) {
-    [accelerated_layer_ setNeedsDisplay];
-    [accelerated_layer_ displayIfNeeded];
+    [accelerated_layer_ immediatelyForceDisplayAndAck];
   }
 
   // If there was a software layer or an old accelerated layer, remove it.
   // Disable the fade-out animation as the layer is removed.
   {
     [software_layer_ removeFromSuperlayer];
     software_layer_.reset();
     [old_accelerated_layer resetClient];
     [old_accelerated_layer removeFromSuperlayer];
     old_accelerated_layer.reset();
   }
 }
 
 - (void)gotSoftwareFrame:(cc::SoftwareFrameData*)frame_data
          withScaleFactor:(float)scale_factor
               withCanvas:(SkCanvas*)canvas {
   if (!frame_data || !canvas)
     return;
 
+  // If the client that requested frame has disappeared, quit immediately (no
+  // acknowledgement is needed to un-block the software compositor).
+  if (!client_)
+    return;
+
   // If there is not a layer for software frames, create one.
   if (!software_layer_) {
     // Disable the fade-in animation as the layer is added.
     ScopedCAActionDisabler disabler;
     software_layer_.reset([[SoftwareLayer alloc] init]);
     [[self layer] addSublayer:software_layer_];
   }
 
   SkImageInfo info;
   size_t row_bytes;
@@ skipping 41 matching lines @@
 
 void BrowserCompositorViewCocoaHelper::AcceleratedLayerDidDrawFrame(
     bool succeeded) {
   [view_ layerDidDrawFrame];
   if (!succeeded)
     [view_ gotAcceleratedLayerError];
 }
 
 }