Don't allow multiple opens for Pepper FileSystem.

Don't allow multiple opens for Pepper FileSystem.

BUG=73667
TEST=test_file_system.{h,cc}

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=76278

[yzshen1, 2011-02-26 19:22:05]

Hi, Brett.

I have considered to return PP_ERROR_INPROGRESS when we are waiting for a
previous open to finish. There are two approaches:
1) add a callback for PPB_FileSystem_Impl, so that it can be notified when the
open operation has failed and FileCallbacks::DidFail gets called.
2) slightly change the logic of FileCallbacks::DidOpenFileSystem or
FileCallbacks::DidFail.

Solution (1) adds an extra layer of callback just to keep track of whether the
open operation has completed. It seems not worthwhile to me.
Solution (2) needs to change the behavior of FileCallbacks, which implements an
interface that is shared by other implementations. I don't think that is a good
idea.

So I didn't put in the code to return PP_ERROR_INPROGRESS for
PPB_FileSystem_Impl.
Please let me know if you don't think this is correct.

Thanks!

[brettw, 2011-02-26 19:32:57]

Looks great, thanks for the new test file. LGTM