Implements core logic for Pixel Canvas

ui/compositor/layer.cc

Index: ui/compositor/layer.cc
diff --git a/ui/compositor/layer.cc b/ui/compositor/layer.cc
index e4d00e84981709dfca106f92557c2c2fb7f45cc8..0ba661e1117fa2fb19bde4678642094318745b77 100644
--- a/ui/compositor/layer.cc
+++ b/ui/compositor/layer.cc
@@ -934,8 +934,11 @@ scoped_refptr<cc::DisplayItemList> Layer::PaintContentsToDisplayList(
   paint_region_.Clear();
   auto display_list = make_scoped_refptr(new cc::DisplayItemList);
   if (delegate_) {
-    delegate_->OnPaintLayer(
-        PaintContext(display_list.get(), device_scale_factor_, invalidation));
+    bool is_pixel_canvas = GetCompositor() ? GetCompositor()->is_pixel_canvas()

[danakj, 2017/07/25 17:58:56]

A layer can't paint without being part of a compositor, can it?

[malaykeshav, 2017/07/25 22:57:57]

yes, but it does not work for layers set as mask. Adding a fix for it.

+                                           : IsPixelCanvasRecordingEnabled();
+    delegate_->OnPaintLayer(PaintContext(display_list.get(),
+                                         device_scale_factor_, invalidation,
+                                         is_pixel_canvas));
   }
   display_list->Finalize();
   // TODO(domlaskowski): Move mirror invalidation to Layer::SchedulePaint.