Move webkit/user_agent/ into webkit/common

chrome/browser/DEPS

 include_rules = [
   "+apps",
   "+breakpad",
   "+chrome/app",
   "+chrome/installer",
   "+chrome/tools/profiles",  # For history unit tests.
   "+chromeos",
   "+components/autofill/browser",
   "+components/autofill/common",
   "+components/auto_login_parser",
@@ skipping 35 matching lines @@
   "+win8/util",
   "+xib_localizers", # For generated mac localization helpers
 
   # TODO(stuartmorgan): Remove these by refactoring necessary code out of
   # webkit/. See crbug.com/146251
   # DO NOT ADD ANY MORE ITEMS TO THE LIST BELOW!
   "+webkit/appcache",
   "+webkit/base/origin_url_conversions.h",
   "+webkit/blob",
   "+webkit/common/plugins",  # Common plugins functionality.
+  "+webkit/common/user_agent",
   "+webkit/dom_storage/dom_storage_types.h",
   "+webkit/fileapi",
   "+webkit/plugins",  # Defines some types that are marshalled over IPC.
   "+webkit/quota",
-  "+webkit/user_agent",
 
   # TODO(kinuko): Remove all other webkit/* dependencies after we cleaned
   # up webkit/. crbug.com/239710
   "+webkit/browser",
 
   # webkit/glue files are listed individually since they aren't conceptually
   # grouped like the other webkit/ files, and can therefore be tackled one at
   # a time.
   "+webkit/glue/glue_serialize.h",
   "+webkit/glue/image_decoder.h",
@@ skipping 27 matching lines @@
   "+third_party/icu",
   "+third_party/isimpledom",
   "+third_party/leveldatabase",
   "+third_party/libevent",  # For the remote V8 debugging server
   "+third_party/libjingle",
   "+third_party/protobuf/src/google/protobuf",
   "+third_party/re2",
   "+third_party/sqlite",
   "+third_party/undoview",
 ]