Add Android-specific parameters to search_engines/

Previous attempt; expanded since then:
https://chromiumcodereview.appspot.com/10332156/

* The search string has "sourceid=chrome-mobile" on Android devices.

* SearchTermsDataAndroid added to handle the data values that Android
  needs to store for RLZ tracking.

* UiThreadSearchTermsData calls Android specific functions when being
  asked for rlz= or client= strings.

* ENABLE_RLZ is moved around (or removed) in some cases to allow use of
  the fields even when the RLZ library is not in use.

* The RLZ unit test is changed to account for the way Android sets the 
  RLZ string.

* A new SearchClient unit test is added to check that setting client
  strings works.

BUG=145065

Review URL: https://chromiumcodereview.appspot.com/11448005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@171954 0039d316-1c4b-4281-b951-d872f2087c98
10 files changed