Move webkit/user_agent/ into webkit/common

webkit/user_agent/ defines a tidy little library that depends on almost nothing
and can be used in any process.  This moves it into webkit/common/user_agent/.
It's still linked as a separate component in the shared_library build.

BUG=237267
R=darin

Review URL: https://chromiumcodereview.appspot.com/15702003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@201700 0039d316-1c4b-4281-b951-d872f2087c98
32 files changed