Add asserts to PipeReaderTest to avoid crashing on reading less than expected.
Add asserts to PipeReaderTest to avoid crashing on reading less than expected.

TEST=trybots
BUG=none

Review URL: http://codereview.chromium.org/4499004

git-svn-id: http://src.chromium.org/svn/trunk/src@65240 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 27264fe7d0020e386c944c0fc6c61ab9c76042b8
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser