More gwt-oauth2 enhancements: - Better error handling - Store tokens in localStorage if supported - Add a sample app to request access to various auth providers - Add build.xml file to build, test, and generate javadocs - Add these as verification steps for the MOE build
More gwt-oauth2 enhancements:
- Better error handling
- Store tokens in localStorage if supported
- Add a sample app to request access to various auth providers
- Add build.xml file to build, test, and generate javadocs
- Add these as verification steps for the MOE build

Drop all references to immediate mode and refreshing via iframe. If
this becomes more widely adopted or included in the spec, this can be
re-added.

R=robertvawter
DELTA=937  (654 added, 179 deleted, 104 changed)


Revision created by MOE tool push_codebase.
MOE_MIGRATION=1500

leonousco/google-apis-explorer,mr1azl/google-apis-explorer,erpragatisingh/google-apis-explorer,BORHANUDDIN1/google-apis-explorer,guido-bruzadin/google-apis-explorer,clementdenis/google-apis-explorer,erpragatisingh/google-apis-explorer,BORHANUDDIN1/google-apis-explorer,Durgapaavank/google-apis-explorer,MrLoick/google-apis-explorer,bcblashko/google-apis-explorer,Durgapaavank/google-apis-explorer,mr1azl/google-apis-explorer,bcblashko/google-apis-explorer,lethanhtuanhcm1982/google-apis-explorer,MrLoick/google-apis-explorer,guido-bruzadin/google-apis-explorer,clementdenis/google-apis-explorer,leonousco/google-apis-explorer,rgroult/google-apis-explorer,lethanhtuanhcm1982/google-apis-explorer,rgroult/google-apis-explorer