Patch at https://codereview.chromium.org/2605403002

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/ba3bd9c5fe080d75f8d451709dc42372b9083daa

commit ba3bd9c5fe080d75f8d451709dc42372b9083daa
Author: meacer <meacer@chromium.org>
Date: Fri Jan 06 19:30:25 2017

Fix flaky CertificateReportingService browser tests.

CertificateReportingService browser tests wait for the IO thread
after sending a report or resetting the service. This doesn't seem
reliable and the tests occasionally fail. A better approach is to:
- For reports, wait for requests to be destroyed
(CertificateReportingService unit test already does this).
- For service resets, wait for a callback to be called.

This CL does these: It removes WaitForIOThread calls from the browser
test and replaces them with the above. It also refactors the following:
- RequestObserver is shared between browser and unit tests.
- NetworkDelegate is no longer used in the unit tests. RequestObserver is
used instead.
- All tests now expect no URL requests to remain during tear down.
- The code to check expected reports is now shared.

BUG= 677560 

Review-Url: https://codereview.chromium.org/2605403002
Cr-Commit-Position: refs/heads/master@{#442008}

[modify] https://crrev.com/ba3bd9c5fe080d75f8d451709dc42372b9083daa/chrome/browser/safe_browsing/certificate_reporting_service.cc
[modify] https://crrev.com/ba3bd9c5fe080d75f8d451709dc42372b9083daa/chrome/browser/safe_browsing/certificate_reporting_service.h
[modify] https://crrev.com/ba3bd9c5fe080d75f8d451709dc42372b9083daa/chrome/browser/safe_browsing/certificate_reporting_service_browsertest.cc
[modify] https://crrev.com/ba3bd9c5fe080d75f8d451709dc42372b9083daa/chrome/browser/safe_browsing/certificate_reporting_service_factory.cc
[modify] https://crrev.com/ba3bd9c5fe080d75f8d451709dc42372b9083daa/chrome/browser/safe_browsing/certificate_reporting_service_factory.h
[modify] https://crrev.com/ba3bd9c5fe080d75f8d451709dc42372b9083daa/chrome/browser/safe_browsing/certificate_reporting_service_test_utils.cc
[modify] https://crrev.com/ba3bd9c5fe080d75f8d451709dc42372b9083daa/chrome/browser/safe_browsing/certificate_reporting_service_test_utils.h
[modify] https://crrev.com/ba3bd9c5fe080d75f8d451709dc42372b9083daa/chrome/browser/safe_browsing/certificate_reporting_service_unittest.cc

Keeping the bug open to verify the flakes are gone.

Looks like they are indeed gone.