GitLab

Reads on the Windows impl of SerialConnection were erroneously set to
wait for up to 10ms before completing with less than the requested
amount of data.

They will now complete immediately with any available data, without
waiting.

BUG=324886

Review URL: https://codereview.chromium.org/100813002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@238367 0039d316-1c4b-4281-b951-d872f2087c98