[BrowserThread] Migrate callers explicitly using content::

Note to QA: This CL is purely mechanical and shouldn't be blamed
for future regressions on touched files.

Only migrate explicit usage of content::BrowserThread in step #1 as
these are the only ones that clearly map to a fully qualified call to
content::Get(UI|IO)ThreadTaskRunner().

Script @ https://crbug.com/1026641#c91

Will make BrowserTaskTraits optional when empty in a follow-up
(can't before end of migration because of cyclic dependency between
browser_thread.h and browser_task_traits.h).

(will TBR fdoray@ post-review for mechanical change)
[email protected]

AX-Relnotes: n/a.
Bug: 1026641
Change-Id: I27615773472c97d9bfd981c8c9e783c26525b51a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2211138
Reviewed-by: Gabriel Charette <[email protected]>
Reviewed-by: François Doray <[email protected]>
Commit-Queue: Gabriel Charette <[email protected]>
Auto-Submit: Gabriel Charette <[email protected]>
Cr-Commit-Position: refs/heads/master@{#772055}
diff --git a/chrome/browser/browser_process_impl.cc b/chrome/browser/browser_process_impl.cc
index 1395818..db2c5764 100644
--- a/chrome/browser/browser_process_impl.cc
+++ b/chrome/browser/browser_process_impl.cc
@@ -1317,7 +1317,7 @@
 
   optimization_guide_service_ =
       std::make_unique<optimization_guide::OptimizationGuideService>(
-          base::CreateSingleThreadTaskRunner({content::BrowserThread::UI}));
+          content::GetUIThreadTaskRunner({}));
 }
 
 void BrowserProcessImpl::CreateGCMDriver() {
@@ -1344,8 +1344,7 @@
       system_network_context_manager()->GetSharedURLLoaderFactory(),
       content::GetNetworkConnectionTracker(), chrome::GetChannel(),
       gcm::GetProductCategoryForSubtypes(local_state()),
-      base::CreateSingleThreadTaskRunner({content::BrowserThread::UI}),
-      base::CreateSingleThreadTaskRunner({content::BrowserThread::IO}),
+      content::GetUIThreadTaskRunner({}), content::GetIOThreadTaskRunner({}),
       blocking_task_runner);
 #endif  // defined(OS_ANDROID)
 }