To clarify, this is about the LOAD_DISABLE_CACHE load flag. So if I'm understanding this correctly, it's mostly a bug in the behavior of HTTP_CACHE_DISK_NO_HTTP, but has some effects on the HostCache and maybe other things I don't know about in the case of HTTP_CACHE_DISABLED.

Yikes CronetURLRequestAdapter() reads from CronetURLRequestContextAdapter::default_load_flags_...which isn't initialized until CronetURLRequestContextAdapter::InitializeOnNetworkThread()

Yup, that's what I found. If not for this bug, testHostCachePersistence would have failed every time instead of about 1% of the time. I'm fixing it now.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/5b7eb518eef51dfbc0fbc05330dfba8994863f92

commit 5b7eb518eef51dfbc0fbc05330dfba8994863f92
Author: Miriam Gershenson <mgersh@chromium.org>
Date: Mon Jul 17 20:34:04 2017

Fix Cronet load flag initialization

Load flags were being read from the CronetURLRequestContextAdapter
on the main thread, which could potentially happen before they were
initialized on the network thread if a UrlRequest is created immediately
after the CronetEngine. Now they are read at request start time on the
network thread, which must be after context initialization.

BUG= 743232 

Change-Id: I3f9c5cd1cde906555c5ba68b4a45a9a3ee71b014
Reviewed-on: https://chromium-review.googlesource.com/574827
Reviewed-by: Paul Jensen <pauljensen@chromium.org>
Commit-Queue: Miriam Gershenson <mgersh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#487227}
[modify] https://crrev.com/5b7eb518eef51dfbc0fbc05330dfba8994863f92/components/cronet/android/cronet_url_request_adapter.cc
[modify] https://crrev.com/5b7eb518eef51dfbc0fbc05330dfba8994863f92/components/cronet/android/cronet_url_request_context_adapter.cc
[modify] https://crrev.com/5b7eb518eef51dfbc0fbc05330dfba8994863f92/components/cronet/android/cronet_url_request_context_adapter.h
[modify] https://crrev.com/5b7eb518eef51dfbc0fbc05330dfba8994863f92/components/cronet/android/test/javatests/src/org/chromium/net/CronetUrlRequestContextTest.java