ozone: Add atomic initialization path

chrome/browser/chromeos/login/chrome_restart_request.cc

Index: chrome/browser/chromeos/login/chrome_restart_request.cc
diff --git a/chrome/browser/chromeos/login/chrome_restart_request.cc b/chrome/browser/chromeos/login/chrome_restart_request.cc
index 3ef1d9c31a5e6680bf6d0eb982c84f5a3207eb02..48339e1434f914fa8848d4a67d23be93f9d01e08 100644
--- a/chrome/browser/chromeos/login/chrome_restart_request.cc
+++ b/chrome/browser/chromeos/login/chrome_restart_request.cc
@@ -168,6 +168,7 @@ std::string DeriveCommandLine(const GURL& start_url,
     ::switches::kOzoneInitialDisplayPhysicalSizeMm,
     ::switches::kOzonePlatform,
     ::switches::kOzoneUseSurfaceless,
+    ::switches::kOzoneUseAtomicDrm,

[dnicoara, 2015/05/19 17:13:14]

This is a platform specific flag. I know that this adds limitations but, I don't
think we want to start adding platform specific flags outside the platform.

[achaulk, 2015/05/19 17:15:44]

The other option is to add a new platform drm_atomic

[dnicoara, 2015/05/19 17:21:58]

Well, we could just make it a compile time flag. I know that having it as a flag
will make it easier to switch between the two during initial
development/debugging, but other than that we expect to just move towards the
atomic API and even deprecate the old path if possible.

[achaulk, 2015/05/19 17:27:36]

Yeah, at which point we rip out the flag. The goal is to make it so you don't
need a custom build to use this path, which means compile time isn't necessarily
enough

[dnicoara, 2015/05/19 17:54:06]

I still don't see much value outside your development workflow, but I do see
this creating precedent on sprinkling platform specific flags outside the
platform code.

Lets proceed with relying on USE_DRM_ATOMIC and drmSetClientCap() to enable
atomic.

 #endif
     app_list::switches::kDisableSyncAppList,
     app_list::switches::kEnableSyncAppList,