Revert "Migrate client_update::SendProtocolRequest to SimpleURLLoader"

This reverts commit ccd4ec0882bbc5d235b49188ca6cc3ac43c6c9d5.

Reason for revert: multiple tests failing on https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/Linux%20Tests%20(dbg)(1)(32)/50984

UpdateServiceTest.UninstallExtensionWhileUpdating
PolicyUpdateServiceTest.PolicyCorruptedOnStartup
PolicyUpdateServiceTest.FailedUpdateRetries
UpdateServiceTest.TwoUpdateCheckErrors
UpdateServiceTest.UpdateCheckError
UpdateServiceTest.SuccessfulUpdate
ComponentUpdaterPolicyTest.EnabledComponentUpdates
PolicyUpdateServiceTest.Backoff
UpdateServiceTest.PolicyCorrupted
UpdateServiceTest.NoUpdate

[5637:5892:0628/072239.370548:FATAL:http_request_headers.cc(129)] "POST /pinghost/service/ping HTTP/1.1" is missing colon delimiter.
 


Original change's description:
> Migrate client_update::SendProtocolRequest to SimpleURLLoader
> 
> URLFetcher et al will stop working in the browser process with advent
> of Network Service, and SimpleURLLoader is the replacement API
> for most clients. CL migrates SendProtocolRequest to the new API.
> 
> Major remarks:
> 
> * URLRequestPostInterceptor is replaced by URLLoaderPostInterceptor although the public APIs
> of the former is kept (are almost the same) in the later. This allows the extensive set of unit
> tests to remain untouched. The replacement is needed because URLRequestPostInterceptor used
> to intercept requests instantiated by URLFetcher, precisely the class we are moving away to use.
> 
> * URLLoaderPostInterceptor operates in two modes: it supports working both with TestURLLoaderFactory
> and EmbeddedTestServer. Two constructors are offered that control the 'mode' it operates on.
> This is needed because of the nature of the tests: some tests manipulate the TestConfigurator
> directly, hence the needed SharedURLLoaderFactory instance can be acquired directly from it,
> eg PingManagerTest, UpdateCheckerTest and RequestSenderTest.
> Some other tests, trigger the respective SimpleURLLoader machinery from upper layers, and then
> have no access to TestConfigurator instances. In such cases, URLLoaderPostInterceptor operates
> using EmbeddedTestServer in order to intercept URL loads.
> 
> Note that this CL migrates components/update_client/utils.cc|h to SimpleURLLoader, but there
> some other classes on the same directory that still use URLFetcher (eg UrlFetcherDownloader),
> so we simply can not *yet* remove all the references to URLFetcher and URLRequestContextGetter.
> It will be done in a follow up CL.
> 
> BUG=773295,844973
> 
> Cq-Include-Trybots: luci.chromium.try:ios-simulator-full-configs;master.tryserver.chromium.mac:ios-simulator-cronet
> Change-Id: I3d8be368818ba77b559907c0217995f8c6a95b04
> Reviewed-on: https://chromium-review.googlesource.com/1097337
> Commit-Queue: Antonio Gomes <tonikitoo@igalia.com>
> Reviewed-by: Maksim Ivanov <emaxx@chromium.org>
> Reviewed-by: Sorin Jianu <sorin@chromium.org>
> Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
> Reviewed-by: David Roger <droger@chromium.org>
> Reviewed-by: Matt Menke <mmenke@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#571097}

TBR=droger@chromium.org,rdevlin.cronin@chromium.org,mmenke@chromium.org,sorin@chromium.org,emaxx@chromium.org,tonikitoo@igalia.com,mxnguyen@chromium.org

Change-Id: I0974aeef814ac153bf7da86ebf3e2f09b410bdd6
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 773295, 844973
Cq-Include-Trybots: luci.chromium.try:ios-simulator-full-configs;master.tryserver.chromium.mac:ios-simulator-cronet
Reviewed-on: https://chromium-review.googlesource.com/1118585
Reviewed-by: Olga Sharonova <olka@chromium.org>
Commit-Queue: Olga Sharonova <olka@chromium.org>
Cr-Commit-Position: refs/heads/master@{#571125}
25 files changed