Fix build of upstream Chromium's unit_tests & browser_tests targets

[mariospr]

Three build failures are currently preventing us from building these
unit_tests & browser_test binaries from upstream:

1. A compilation error due to FakeDeviceInfoTracker not implementing
   Brave-specific's GetAllBraveDeviceInfo() and DeleteDeviceInfo()
   virtual methods from DeviceInfoTracker (added via an override).

2. A compilation error in //c/b/apps/guest_view/web_view_browsertest.cc
   because of testing code using RenderViewContextMenu's static method
   RegisterMenuShownCallbackForTesting(), which would expect a callback
   |base::OnceCallback<void(RenderViewContextMenu_Chromium*>| because
   of the source override in chromium_src/c/b/renderer_context_menu, but
   a |base::OnceCallback<void(BraveRenderViewContextMenu*)>| will be
   passed instead due to the redefinition set in that source override.

3. A linking error due to push_messaging_service_unittest.cc requiring
   a dependency for BraveTestingProfile (also added via an override).

This patches fixes all those three errors via chromium overrides and
a small patch to //chrome/test/BUILD.gn to add a missing dependency.

Fix brave/brave-browser#14001

Resolves brave/brave-browser#14001

Submitter Checklist:

• There is a ticket for my issue.
• Used Github auto-closing keywords in the commit message.
• Wrote a good PR/commit description
• Added appropriate labels (QA/Yes or QA/No; release-notes/include or release-notes/exclude; OS/...) to the associated issue
• Checked the PR locally: npm run test -- brave_browser_tests, npm run test -- brave_unit_tests, npm run lint, npm run gn_check, npm run tslint
• Ran git rebase master (if needed).
• Requested a security/privacy review as needed.

Reviewer Checklist:

• New files have MPL-2.0 license header.
• Adequate test coverage exists to prevent regressions
• Major classes, functions and non-trivial code blocks are well-commented
• Changes in component dependencies are properly reflected in gn
• Code follows the style guide
• Test plan is specified in PR before merging

After-merge Checklist:

• The associated issue milestone is set to the smallest version that the
  changes has landed on.
• All relevant documentation has been updated, for instance:
  • https://github.com/brave/brave-browser/wiki/Deviations-from-Chromium-(features-we-disable-or-remove)
  • https://github.com/brave/brave-browser/wiki/Proxy-redirected-URLs
  • https://github.com/brave/brave-browser/wiki/Fingerprinting-Protections
  • https://github.com/brave/brave-browser/wiki/Brave%E2%80%99s-Use-of-Referral-Codes
  • https://github.com/brave/brave-browser/wiki/Custom-Headers
  • https://github.com/brave/brave-browser/wiki/Web-Compatibility-Exceptions-in-Brave
  • https://github.com/brave/brave-browser/wiki/QA-Guide
  • https://github.com/brave/brave-browser/wiki/P3A

Test Plan:

N/A

[mariospr]

@bridiver and/or @mkarolin PTAL to this small PR to enable building the unit_tests binary, so that we can resume work on brave/brave-browser#8376. Thanks!

[mariospr]

FWIW, the failure in the linux CI bot is unrelated to this change (i.e. a pre-existing issue on master):

[2021-02-12T18:46:24.554Z] 1 test failed:
[2021-02-12T18:46:24.554Z]     BraveShieldsAPIBrowserTest.AllowScriptsOnceIframe (../../brave/browser/extensions/api/brave_shields_api_browsertest.cc:185)

[mariospr]

@bridiver @iefremov Pinging you on this again, thanks!

Note: this patch is a dependency of both brave/brave-browser#8376 and brave/brave-browser#8297

[bridiver]

what is this for?

[mariospr]

This is to fix a linking error that happens because of the push_messaging_service_unittest.cc having a dependency on BraveTestingProfile (via a chromium_src override) that needs to be satisfied.

Without this bit, the following error happens at link time:

ld.lld: error: undefined symbol: BraveTestingProfile::BraveTestingProfile()
>>> referenced by push_messaging_service_unittest.cc:73 (/home/mario/work/brave-browser/src/brave/chromium_src/chrome/browser/push_messaging/../../../../../chrome/browser/push_messaging/push_messaging_service_unittest.cc:73)
>>>               obj/chrome/test/unit_tests/push_messaging_service_unittest.o:((anonymous namespace)::PushMessagingTestingProfile::PushMessagingTestingProfile())
>>> did you mean: BraveTestingProfile::~BraveTestingProfile()
>>> defined in: obj/chrome/test/unit_tests/push_messaging_service_unittest.o

[bridiver]

I think maybe it's best to insert brave_testing_profile into the testing_profile .h/.cc through chromium_src overrides and then they'll be available here without any patches

[mariospr]

I didn't realize I could do that, thanks for the suggestion.

PR updated!