GitLab

A URLRequest can signal the end of a stream by calling OnReadCompleted()
with a byte count of zero. No further reads should be issued after this.
However, ResourceLoader could issue a second Read() if the
ResourceHandler::OnReadCompleted() handler sets defer to true. I.e.

When a read completes:
  URLRequest calls
    -> ResourceLoader::OnReadCompleted(request, 0)
    -> ResourceHandler::OnReadCompleted(id, 0, &defer)
       (ResourceHandler sets defer to true)

Prior to this CL, the behavior on resumption was:

  ResourceHandler calls
    -> ResourceLoader::Resume()
    -> ResourceLoader::ResumeReading()
    -> ResourceLoader::StartReading()
    -> ResourceLoader::ReadMore()
    -> URLRequest::Read()

The new behavior is:

  ResourceHandler calls
    -> ResourceLoader::Resume()
    -> ResourceLoader::ResponseCompleted()

The new behavior is parallel to what happens if the ResourceHandler
didn't defer.

BUG=320394

Review URL: https://codereview.chromium.org/267563004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@269518 0039d316-1c4b-4281-b951-d872f2087c98