Limit apparent duration of decoded file for WebAudio on Android

If the duration of an encoded audio file is unreasonably large, set
the duration to 0, which forces the caller not to preallocate space.
Instead the file will be decoded in chunks and buffered until the
decoding is done. This works around the incredibly huge duration
returned by MediaFormat in the bug report.

This has a side effect that we now end up using twice as much space in
the caller because it has to buffer the data until complete and then
copy it all to the final audio bus.

BUG=326856

Review URL: https://codereview.chromium.org/133583007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@246460 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 246460
[NaCl SDK] Make ARM cross compiler optional until trybots get updated.

This change, combined with the recent revert of the SDK ARM
components on in the NaCl tree (https://codereview.chromium.org/141733005/)
should allow the SDK builders to go green again.

BUG=335303
R=binji@chromium.org

Review URL: https://codereview.chromium.org/132523006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@246461 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 246461