Create TetherService, a TetherAllowed pref, and use DependencyManager for RegisterProfilePrefs call…

chrome/browser/BUILD.gn

Index: chrome/browser/BUILD.gn
diff --git a/chrome/browser/BUILD.gn b/chrome/browser/BUILD.gn
index cda77e2c4d0a884b4fe3fa9842735e571fca09bc..832a6189905f792fea2e5201e9304bb41e702a98 100644
--- a/chrome/browser/BUILD.gn
+++ b/chrome/browser/BUILD.gn
@@ -3575,6 +3575,10 @@ split_static_library("browser") {
       "task_manager/task_manager_interface.h",
       "task_manager/task_manager_observer.cc",
       "task_manager/task_manager_observer.h",
+      "tether/tether_service.cc",

[Lei Zhang, 2017/04/19 19:13:17]

Is this going to build on Windows/Mac/Linux too? You should run some try jobs
when you get closer to be able to submit.

[Ryan Hansberry, 2017/04/20 17:22:32]

This is only intended to run on ChromeOS.

[Lei Zhang, 2017/04/20 19:17:14]

So why is not in a ChromeOS only source list? (see line 3199 where this section
starts)

[Lei Zhang, 2017/04/20 19:24:30]

Another question - is this ever going to be used on Windows/Mac/Linux? If not,
you can leave it here, but rename the files to have the _chromeos postfix. e.g.
tether/tether_service_chromeos.cc. Then it won't be built on other platforms.

[Ryan Hansberry, 2017/04/20 22:08:09]

I've moved these under a is_chromeos source list. Let me know if that's
incorrect (And there are no plans to expand this to platforms other than
ChromeOS).

[Lei Zhang, 2017/04/20 22:11:43]

Why not just rename the file so it is immediately obvious that the file is
platform specific?

[Ryan Hansberry, 2017/04/20 22:26:45]

What's the preferred situation:

1) Place tether_service_* under the non-Android source set it was with the
suffix _chromeos
2) Place tether_service_* under this is_chromeos source set without the suffix
_chromeos
3) Place tether_service_* under this is_chromeos source set and use the suffix
_chromeos
4) Place tether_service_* files under chrome/browser/chromeos

?

+      "tether/tether_service.h",
+      "tether/tether_service_factory.cc",
+      "tether/tether_service_factory.h",
       "themes/browser_theme_pack.cc",
       "themes/browser_theme_pack.h",
       "themes/custom_theme_supplier.cc",