Unlike GetOSFileDescriptor, this API is asynchronous.
Both GetOSFileDescriptor and RequestOSFileHandle use GetOSFileDescriptor
chrome IPC for now. I'm planning to remove call sites of
GetOSFileDescriptor PPAPI and rename GetOSFileDescriptor chrome IPC to
RequestOSFileHandle.

- Add --allow-get-os-file-handle-api. With this flag,
  1. browser_tests can test this API and 2. we can use this API even
  before this issue is resolved: http://crbug.com/224123
- Add TestRequestOSFileHandle in FileIO. This checks if read, write,
  lseek, and mmap work for FD fetched by this API.
- PepperFileIOHost::OnHostMsgGetOSFileDescriptor use
  ShareHandleWithRemote to pass a file handle
- Fix ShareHandleWithRemote for in-process API

BUG=183015
TEST=trybots, browser_tests

Review URL: https://chromiumcodereview.appspot.com/13032002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@191616 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/ppapi/ppapi_sources.gypi b/ppapi/ppapi_sources.gypi
index 3669be6..cf01f08 100644
--- a/ppapi/ppapi_sources.gypi
+++ b/ppapi/ppapi_sources.gypi
@@ -273,6 +273,8 @@
       # Private interfaces.
       'cpp/private/content_decryptor_private.cc',
       'cpp/private/content_decryptor_private.h',
+      'cpp/private/file_io_private.cc',
+      'cpp/private/file_io_private.h',
       'cpp/private/flash.cc',
       'cpp/private/flash.h',
       'cpp/private/flash_clipboard.cc',