Mac: Towards moving CALayerTree to the browser proc

ui/accelerated_widget_mac/DEPS

Index: ui/accelerated_widget_mac/DEPS
diff --git a/ui/accelerated_widget_mac/DEPS b/ui/accelerated_widget_mac/DEPS
index ae409b796f067bbfacbf4433067eb8d601f62283..8dac1d663011a4a6744609335e1ffda537ac3d7b 100644
--- a/ui/accelerated_widget_mac/DEPS
+++ b/ui/accelerated_widget_mac/DEPS
@@ -1,9 +1,12 @@
 include_rules = [
+  "+gpu/GLES2",

[no sievers, 2016/04/20 00:20:14]

That dependency seems backwards. Can you add the macros in ui/gl/gl_bindings.h
and then include that from ca_layer_tree_mac.mm?

[ccameron, 2016/04/20 07:17:15]

Are you sure? This is used to define GL_CA_LAYER_EDGE_RIGHT_CHROMIUM, which is
then used in cc/output/ca_layer_overlay.cc.

That's where things get disastrous. Because ui/ tends to include  the <GL/gl.h>,
while cc/ tends to include "third_party/khronos/GLES2/gl2ext.h".

Trying to get ui/gl_bindings.h into cc/ seems to have been repeatedly attempted
and failed -- see crbug.com/512833.

After several hours fighting with this, I give up.

Two options
1. Leave things as they are. Once the move to the browser process is complete,
we can just remove the GLES2 dependency, since we no longer need to go through
the command buffer.
2. Create a ui/gl/gl_bindings_chromium.h, which #defines all of the _CHROMIUM
values, and doesn't include any of the system headers. That file could then be
included without fear of conflicts.

Which would you prefer?

   "+third_party/skia",
   "+ui/base/cocoa",
   "+ui/base",
   "+ui/events",
+  "+ui/gfx",
   "+ui/gfx/geometry",
+  "+ui/gfx/mac",
   "+ui/gfx/native_widget_types.h",
   "+ui/gl",
 ]