Add OBSOLETE to DOMApplicationCache prototype.

R=nicksantos
DELTA=6 (6 added, 0 deleted, 0 changed)


Revision created by MOE tool push_codebase.
MOE_MIGRATION=6095


git-svn-id: http://closure-compiler.googlecode.com/svn/trunk@2450 b0f006be-c8cd-11de-a2e8-8d36a3108c74