Change google_api::RequestSender to take an AuthService instead of a Profile.

Change google_api::RequestSender to take an AuthService instead of a Profile.

This way, we can plug-in a dummy instance of AuthService in tests, and then
* We can remove TestingProfile completely from c/b/google_apis/.
* Several for_testing() methods can be removed.
* Switching the internals of AuthService to OAuth2TokenService (162157)
gets more smooth, since tests for request classes are
completely separated from AuthService.

BUG=162157
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=212079

[kinaba, 2013-07-17 05:13:03]

+satorux: ptal.

Here's the context of this patch. I'm now planning to proceed the dependency
clearance by:

1. Switch the implementation of AuthService from TokenService to
OAuth2TokenService. At this point, AuthService still refers to
chrome/browser/profile to retrieve ProfileOAuth2TokenService.

2. Then after that, make it possible to inject ProfileOAuth2TokenService from
outside.

rogerta@ is preparing a patch for the 1st part (thanks!) now,
but it has to introduce additional dependency derived from
ProfileOAuth2TokenService
into c/b/google_apis tests. The current patch I'm requesting reviews
is for saving us from the situation. (And even if we didn't have the
concern, I believe this change is good for our code clarity.)

[satorux1, 2013-07-17 05:37:18]

LGTM. sounds like a reasonable approach.

[commit-bot: I haz the power, 2013-07-17 05:40:24]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/kinaba@chromium.org/19511002/1

[commit-bot: I haz the power, 2013-07-17 13:48:55]

Retried try job too often on win7_aura for step(s) content_browsertests
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=win7_aura&...

[commit-bot: I haz the power, 2013-07-17 14:02:55]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/kinaba@chromium.org/19511002/1

[commit-bot: I haz the power, 2013-07-17 17:22:50]

Change committed as 212079