Avoid using two-phase read with MOJO_READ_DATA_FLAG_ALL_OR_NONE.

Avoid using two-phase read with MOJO_READ_DATA_FLAG_ALL_OR_NONE.

The issue is that when we get close to the end of data pipe's buffer, the call may fail because the distance between the read cursor to the end of the buffer is smaller than the requested size. In that case, even if the buffer contains sufficient data (possible because it is circular), such a read request will never succeed.

Please see https://github.com/domokit/mojo/issues/366 for more details.

BUG=513789
Committed: https://crrev.com/c40ee5271fa911b80341a93e318cb90df7354b51
Cr-Commit-Position: refs/heads/master@{#342626}

[yzshen1, 2015-08-07 23:17:41]

yzshen@chromium.org changed reviewers:
+ jam@chromium.org

[yzshen1, 2015-08-07 23:17:41]

Hi, John.

Would you please take a look? Thanks!

[jam, 2015-08-10 14:56:00]

lgtm

[yzshen1, 2015-08-10 15:47:42]

The CQ bit was checked by yzshen@chromium.org

[commit-bot: I haz the power, 2015-08-10 15:47:51]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1281073003/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1281073003/20001

[commit-bot: I haz the power, 2015-08-10 16:00:06]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-08-10 16:00:33]

Patchset 2 (id:??) landed as
https://crrev.com/c40ee5271fa911b80341a93e318cb90df7354b51
Cr-Commit-Position: refs/heads/master@{#342626}