Mustash: move content::GPUVideoMemoryUsageStats to gpu::VideoMemoryUsageStats

content/gpu/BUILD.gn

Index: content/gpu/BUILD.gn
diff --git a/content/gpu/BUILD.gn b/content/gpu/BUILD.gn
index 3bc1845a82ee9a5685e7f1a7b7cd83f810bcfe6c..8877864365806804569b146a1e48740438c9b138 100644
--- a/content/gpu/BUILD.gn
+++ b/content/gpu/BUILD.gn
@@ -44,6 +44,7 @@ source_set("gpu_sources") {
     "//base",
     "//content:export",
     "//content/public/child:child_sources",
+    "//gpu/ipc/common:ipc_common_sources",

[Nico, 2016/02/24 15:15:17]

This looks really questionable. ipc_common_sources sets GPU_IMPLEMENTATION, so
it'll export all its things – so it must only be linked into the gpu component.
This adds it to the content component too, and then exports them too.

Arguably things are even worse in the gyp build as far as I can tell:
gpu_ipc_common is a static_library but doesn't set GPU_IMPLEMENTATION, so all
the GPU_EXPORTs in that target are effectively ignored and the static library is
linked into many components.

The way this should work is one of these two things:

1. Export these classes only from gpu, which means depending on
ipc_common_sources _only_ from the gpu target

2. Make ipc_common_sources its own component with its own _EXPORT macro.

I don't know what you're trying to do so I can't recommend which of these is
right for you (generally, I'd guess 2). I'm happy to review this part in a fixed
patch set or advise on this (but your original reviewers will be able to do this
too)

[Mark Dittmer, 2016/02/25 16:06:53]

Thanks for the thorough feedback! Based on how much more we anticipate putting
in ipc/common I think I'll implement 1. Will ping when updated gn/gyp files are
ready.

     "//mojo/shell/public/interfaces",
     "//skia",
     "//ui/gl",