[PPAPI] Moving pp::VarResource_Dev API into pp::Var (now stable).
This API allows pp::Resource objects to be read and written to pp::Vars.
Moved the methods of PPB_VarResource_Dev (C API) to PPB_Var version 1.2.
Moved the methods of pp::VarResource_Dev (C++ API) to pp::Var.
Code written against the dev API will no longer compile, as references
to the API need to be updated to use Var instead of VarResource_Dev.
Binaries compiled against the dev API will now experience run-time
errors loading the old interface.
BUG=177017
Review URL: https://codereview.chromium.org/
148213016
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251000 0039d316-1c4b-4281-b951-d872f2087c98