And, which I forgot to include, the whole of gltf_controller.cc and gltf_controller.h should probably also be excluded.

(I don't know this code, this is mostly based on what code calls which other code)

Seems the reason it normally works is that the root of all references are the ui_* files, ui.cc, ui_element_renderer.cc, ui_input_manager.cc, ui_renderer.cc and ui_scene_creator.cc and they are all unused. Since they are unused, the generated object files will be ignored by the linker and everything they depend on will be ignored so it doesn't matter that they contain dangling references.

So the ui_*.cc files should be moved from "vr_common", but I'm not sure where. To test_support and testapp/BUILD.gn? Or should there be a new mini sourceset with just those?

This doesn't mean that the the code setup in the rest of the code is correct but it explains why it compiles in normal builds.

What are your gn.args, your platform and your build target?

This was on Linux and I built chrome and vr_common_unittests.

I'm making a stab at moving the ui files to another target in https://chromium-review.googlesource.com/c/chromium/src/+/913611 but my first attempt (moving to test_support) failed because then the android vr_shell didn't get them.

Oh, and it was a release component build, but you won't get the linker errors that made me notice this with anything checked in so it really doesn't matter.

The UI files need to be in Chrome since they draw the VR UI. I'm unsure, which build failed for you. Can you give me the exact gn.args for that?

Could it be a difference between Chromium and Chrome?

https://chromium-review.googlesource.com/c/chromium/src/+/913611 compiles fine without those files so they don't seem to be needed in Chromium.

It's a bit complicated to explain how to reproduce the symptoms locally so I made a CL that will fail to compile in some builders https://chromium-review.googlesource.com/c/chromium/src/+/913952 .

So far it has compiled successfully in Android and Mac but failed in liux_chromium_compile_dbg_ng (see https://ci.chromium.org/p/chromium/builders/luci.chromium.try/linux_chromium_compile_dbg_ng/11374 )

For platforms where enabled_gvr_services is true, it should be fine but I don't know which platforms that is (nor what gvr is. :) ).

Thanks for the info. Can I ask what you are trying to do? Splitting the UI from the rest may not be the best solution.

I don't think there is a Chromium vs Chrome problem. I only build with Chromium, too. GVR is Google's VR rendering library and only available on Android ARM in Chrome.

I tried to jumbo compile chrome/browser/vr ( see https://chromium.googlesource.com/chromium/src/+/master/docs/jumbo.md ) and got some really strange compilation errors. Those made me realize that some code was compiled and then discarded and that the build system even depended on the linker discarding that code (which it stopped doing in a jumbo build).

I am absolutely not familiar with this code so we can discuss (i.e. you can tell me :-) ) what the proper solution would be in the code review.

We do want to compile code on platforms where it is not necessarily in the final product. For example, we do this on Linux to enable testing. (This should only occur when those tests are being built.) However, we should avoid linking it into the final product.

GLTF controller and parser has been removed.