[scheduling] Use ScopedTaskEnvironment instead of MessageLoop in domain_reliability

MessageLoop will go away, eventually.

BUG=891670

Change-Id: I868d222e9f7136c82a1225214f7d4f25652fa083
Reviewed-on: https://chromium-review.googlesource.com/c/1352364Reviewed-by: Asanka Herath <asanka@chromium.org>
Commit-Queue: Carlos Caballero <carlscab@google.com>
Cr-Commit-Position: refs/heads/master@{#613109}

components/domain_reliability/uploader_unittest.cc

@@ -11,9 +11,10 @@
 
 #include "base/bind.h"
 #include "base/memory/ptr_util.h"
-#include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
+#include "base/test/scoped_task_environment.h"
 #include "base/test/test_simple_task_runner.h"
+#include "base/threading/thread_task_runner_handle.h"
 #include "components/domain_reliability/test_util.h"
 #include "net/base/load_flags.h"
 #include "net/http/http_response_headers.h"
@@ -107,9 +108,7 @@ class UploadInterceptor : public net::URLRequestInterceptor {
  public:
   UploadInterceptor() : request_count_(0), last_upload_depth_(-1) {}
 
-  ~UploadInterceptor() override {
-    EXPECT_TRUE(results_.empty());
-  }
+  ~UploadInterceptor() override { EXPECT_TRUE(results_.empty()); }
 
   net::URLRequestJob* MaybeInterceptRequest(
       net::URLRequest* request,
@@ -176,10 +175,11 @@ class DomainReliabilityUploaderTest : public testing::Test {
  protected:
   DomainReliabilityUploaderTest()
       : url_request_context_getter_(new net::TestURLRequestContextGetter(
-            message_loop_.task_runner())),
+            base::ThreadTaskRunnerHandle::Get())),
         interceptor_(new UploadInterceptor()),
-        uploader_(DomainReliabilityUploader::Create(
-            &time_, url_request_context_getter_)) {
+        uploader_(
+            DomainReliabilityUploader::Create(&time_,
+                                              url_request_context_getter_)) {
     net::URLRequestFilter::GetInstance()->AddUrlInterceptor(
         GURL(kUploadURL), base::WrapUnique(interceptor_));
     uploader_->SetDiscardUploads(false);
@@ -191,13 +191,13 @@ class DomainReliabilityUploaderTest : public testing::Test {
 
   DomainReliabilityUploader* uploader() const { return uploader_.get(); }
   UploadInterceptor* interceptor() const { return interceptor_; }
-  scoped_refptr<net::TestURLRequestContextGetter>
-      url_request_context_getter() {
+  scoped_refptr<net::TestURLRequestContextGetter> url_request_context_getter() {
     return url_request_context_getter_;
   }
 
  private:
-  base::MessageLoopForIO message_loop_;
+  base::test::ScopedTaskEnvironment task_environment_{
+      base::test::ScopedTaskEnvironment::MainThreadType::IO};
   scoped_refptr<net::TestURLRequestContextGetter> url_request_context_getter_;
   UploadInterceptor* interceptor_;
   MockTime time_;