Add NSString category for providing iOS6-style string drawing APIs.

ui/ios/ui_ios.gyp

Index: ui/ios/ui_ios.gyp
diff --git a/device/core/core.gyp b/ui/ios/ui_ios.gyp
similarity index 50%
copy from device/core/core.gyp
copy to ui/ios/ui_ios.gyp
index 09bd315330e738ddf64f7e8515facf0d9c42eb6a..afec667c6822e6d6b7e7a7ab5176b7a290b429a4 100644
--- a/device/core/core.gyp
+++ b/ui/ios/ui_ios.gyp
@@ -8,14 +8,19 @@
   },
   'targets': [
     {
-      'target_name': 'device_core',
+      'target_name': 'ui_ios',
       'type': 'static_library',
+      # Linkable dependents need to set the linker flag '-ObjC' in order to use
+      # the categories in this target (e.g. NSString+CrStringDrawing.h).
+      'link_settings': {
+        'xcode_settings': {'OTHER_LDFLAGS': ['-ObjC']},
+      },
       'include_dirs': [
         '../..',
       ],
       'sources': [
-        'device_client.cc',
-        'device_client.h',
+        'NSString+CrStringDrawing.h',
+        'NSString+CrStringDrawing.mm',
       ],
     },
   ],