Add reconnect logic to URLLoaderFactoryBundle

This CL:
1. Allows |RenderFrameHostImpl| to push new |URLLoaderFactoryBundle|
   to |RenderFrameImpl| after navigation so they can send updated
   Network Service factories in case of crash.
2. Adds a 'content_browsertests' to verify XHR still works after
   Network Service crash.

Bug: 780956
Change-Id: I4323648c7475ff311b1e3825aeb804265ad6899c
Reviewed-on: https://chromium-review.googlesource.com/858428
Reviewed-by: Kinuko Yasuda <[email protected]>
Reviewed-by: Ken Rockot <[email protected]>
Commit-Queue: Chong Zhang <[email protected]>
Cr-Commit-Position: refs/heads/master@{#531449}
9 files changed