Add detached mode plumbing

content/common/gpu/ca_layer_tree_mac.mm

Index: content/common/gpu/ca_layer_tree_mac.mm
diff --git a/content/common/gpu/ca_layer_tree_mac.mm b/content/common/gpu/ca_layer_tree_mac.mm
index cac3dfe9ac10de8a00793e059a96180838d3e06c..5e696ac304f3b582d3e92080cea46704bfcdf6a2 100644
--- a/content/common/gpu/ca_layer_tree_mac.mm
+++ b/content/common/gpu/ca_layer_tree_mac.mm
@@ -142,9 +142,12 @@ bool CALayerTree::ScheduleCALayer(
                                      background_color, edge_aa_mask, opacity);
 }
 
-void CALayerTree::CommitScheduledCALayers(CALayer* superlayer,
-                                          scoped_ptr<CALayerTree> old_tree,
-                                          float scale_factor) {
+void CALayerTree::CommitScheduledCALayers(
+    CALayer* superlayer,
+    bool* use_detached_video_layer,
+    AVSampleBufferDisplayLayer* detached_video_layer,
+    scoped_ptr<CALayerTree> old_tree,
+    float scale_factor) {
   TRACE_EVENT0("gpu", "CALayerTree::CommitScheduledCALayers");
   RootLayer* old_root_layer = nullptr;
   if (old_tree) {
@@ -153,6 +156,41 @@ void CALayerTree::CommitScheduledCALayers(CALayer* superlayer,
       old_root_layer = &old_tree->root_layer_;
   }
 
+  // Do the video check.
+  {
+    bool all_before_black = true;
+    bool found_video = false;
+    bool nothing_after = true;
+    ContentLayer* video_layer = nullptr;
+    
+    for (auto& clip_layer : root_layer_.clip_and_sorting_layers) {
+      for (auto& transform_layer : clip_layer.transform_layers) {
+        for (auto& content_layer : transform_layer.content_layers) {
+          if (all_before_black) {
+            if (found_video) {
+              nothing_after = false;
+            }
+            if (content_layer.use_av_layer) {
+              found_video = true;
+              video_layer = &content_layer;
+            } else if (content_layer.background_color & 0x00FFFFFF) {
+              all_before_black = false;
+            }
+          }
+        }
+      }
+    }
+    printf("bb:%d fv:%d na:%d\n", all_before_black, found_video, nothing_after);
+    if (all_before_black && found_video && nothing_after) {
+      printf("YES TO DETACHED MODE!!!\n");
+      *use_detached_video_layer = true;
+      AVSampleBufferDisplayLayerEnqueueIOSurface(detached_video_layer, video_layer->io_surface);
+    } else {
+      *use_detached_video_layer = false;
+    }
+  }
+
+
   root_layer_.CommitToCA(superlayer, old_root_layer, scale_factor);
   // If there are any extra CALayers in |old_tree| that were not stolen by this
   // tree, they will be removed from the CALayer tree in this deallocation.