[MessageLoop]: Replace RunLoop-related ScopedNestableTaskAllower in /content/public/test.

This CL replaces ScopedNestableTaskAllower with kNestableTasksAllowed passed
as argument to the RunLoop involved if any.
Only native nested loops should use ScopedNestableTaskAllower (soon to be deprecated).
For more details, see:
https://cs.chromium.org/chromium/src/base/message_loop/message_loop_current.h?sq=package:chromium&dr=CSs&g=0&l=159

A small step towards deleting MessageLoop.

This CL was generated with git cl split.
Refer to the top-level CL if necessary :
https://chromium-review.googlesource.com/c/chromium/src/+/1635819

Please CQ if LGTY!

This CL was uploaded by git cl split.

R=tommi@chromium.org

Bug: 766678
Change-Id: I5169a00876479db55907237bc3b7dc339f463bb8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1635825
Auto-Submit: Etienne Pierre-Doray <etiennep@chromium.org>
Reviewed-by: Tommi <tommi@chromium.org>
Commit-Queue: Etienne Pierre-Doray <etiennep@chromium.org>
Cr-Commit-Position: refs/heads/master@{#666203}

content/public/test/browser_test_base.cc

@@ -439,7 +439,7 @@ void BrowserTestBase::SimulateNetworkServiceCrash() {
   ServiceManagerConnection::GetForProcess()->GetConnector()->BindInterface(
       mojom::kNetworkServiceName, &network_service_test);
 
-  base::RunLoop run_loop(base::RunLoop::Type::kNestableTasksAllowed);
+  base::RunLoop run_loop{base::RunLoop::Type::kNestableTasksAllowed};
   network_service_test.set_connection_error_handler(run_loop.QuitClosure());
 
   network_service_test->SimulateCrash();
@@ -631,12 +631,10 @@ void BrowserTestBase::InitializeNetworkProcess() {
   ServiceManagerConnection::GetForProcess()->GetConnector()->BindInterface(
       mojom::kNetworkServiceName, &network_service_test);
 
-  // Allow nested tasks so that the mojo reply is dispatched.
-  base::MessageLoopCurrent::ScopedNestableTaskAllower allow;
   // Send the DNS rules to network service process. Android needs the RunLoop
   // to dispatch a Java callback that makes network process to enter native
   // code.
-  base::RunLoop loop;
+  base::RunLoop loop{base::RunLoop::Type::kNestableTasksAllowed};
   network_service_test->AddRules(std::move(mojo_rules), loop.QuitClosure());
   loop.Run();
 }

content/public/test/browser_test_utils.cc

@@ -1844,7 +1844,7 @@ void SetupCrossSiteRedirector(net::EmbeddedTestServer* embedded_test_server) {
 void WaitForInterstitialAttach(content::WebContents* web_contents) {
   if (web_contents->ShowingInterstitialPage())
     return;
-  base::RunLoop run_loop(base::RunLoop::Type::kNestableTasksAllowed);
+  base::RunLoop run_loop{base::RunLoop::Type::kNestableTasksAllowed};
   InterstitialObserver observer(web_contents, run_loop.QuitClosure(),
                                 base::OnceClosure());
   run_loop.Run();
@@ -2246,7 +2246,7 @@ bool DOMMessageQueue::WaitForMessage(std::string* message) {
   DCHECK(message);
   if (!renderer_crashed_ && message_queue_.empty()) {
     // This will be quit when a new message comes in.
-    base::RunLoop run_loop(base::RunLoop::Type::kNestableTasksAllowed);
+    base::RunLoop run_loop{base::RunLoop::Type::kNestableTasksAllowed};
     quit_closure_ = run_loop.QuitClosure();
     run_loop.Run();
   }
@@ -2423,7 +2423,7 @@ void RenderFrameSubmissionObserver::Quit() {
 }
 
 void RenderFrameSubmissionObserver::Wait() {
-  base::RunLoop run_loop;
+  base::RunLoop run_loop{base::RunLoop::Type::kNestableTasksAllowed};
   quit_closure_ = run_loop.QuitClosure();
   run_loop.Run();
 }

content/public/test/frame_load_waiter.h

@@ -28,7 +28,7 @@ class FrameLoadWaiter : public RenderFrameObserver {
   void DidFinishLoad() override;
   void OnDestruct() override;
 
-  base::RunLoop run_loop_;
+  base::RunLoop run_loop_{base::RunLoop::Type::kNestableTasksAllowed};
   bool did_load_ = false;
 
   DISALLOW_COPY_AND_ASSIGN(FrameLoadWaiter);