arc: enable Android tracing from chrome://tracing in dev mode

chrome/browser/chromeos/BUILD.gn

Index: chrome/browser/chromeos/BUILD.gn
diff --git a/chrome/browser/chromeos/BUILD.gn b/chrome/browser/chromeos/BUILD.gn
index d91ac1bd9f5a6753e96daa546558c63dfb57c878..a94e90002188a2de710d4ad1453c35352b2b07e8 100644
--- a/chrome/browser/chromeos/BUILD.gn
+++ b/chrome/browser/chromeos/BUILD.gn
@@ -313,6 +313,8 @@ source_set("chromeos") {
     "arc/process/arc_process.h",
     "arc/process/arc_process_service.cc",
     "arc/process/arc_process_service.h",
+    "arc/trace/arc_trace_bridge.cc",

[Daniel Erat, 2017/03/08 15:41:13]

rename these to arc/tracing/arc_tracing_bridge?

a "trace" is the thing that gets generated, but "tracing" is what these classes
do. "tracing" seems more consistent with existing naming (see
chrome/browser/tracing/, components/tracing/, services/tracing/, etc.).

[Earl Ou, 2017/03/09 06:08:41]

Done. I also change mojom interface to tracing.mojo, TracingInstance etc. On
Android side, it will still be arctraceservice instead of arctracingservice as
we have 16 character limit for service name.

+    "arc/trace/arc_trace_bridge.h",
     "arc/tts/arc_tts_service.cc",
     "arc/tts/arc_tts_service.h",
     "arc/video/gpu_arc_video_service_host.cc",