Remove MessageLoop from omnibox tests.

See the following document for details:
https://docs.google.com/document/d/1QabRo8c7D9LsYY3cEcaPQbOCLo8Tu-6VLykYXyl3Pkk

Bug: 
Change-Id: I49b7f3a00be777a88e5e6c86a4a582da94b917a9
Reviewed-on: https://chromium-review.googlesource.com/783641Reviewed-by: Kevin Bailey <krb@chromium.org>
Commit-Queue: Justin Donnelly <jdonnelly@chromium.org>
Cr-Commit-Position: refs/heads/master@{#518429}

components/omnibox/browser/autocomplete_provider_unittest.cc

@@ -13,13 +13,13 @@
 #include "base/location.h"
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
-#include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/string16.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/test/scoped_task_environment.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "components/omnibox/browser/autocomplete_controller.h"
 #include "components/omnibox/browser/autocomplete_input.h"
@@ -273,7 +273,7 @@ class AutocompleteProviderTest : public testing::Test {
   // platform, flags, etc.) be instantiated.
   void ResetControllerWithType(int type);
 
-  base::MessageLoop message_loop_;
+  base::test::ScopedTaskEnvironment scoped_task_environment_;
   std::unique_ptr<AutocompleteController> controller_;
   // Owned by |controller_|.
   AutocompleteProviderClientWithClosure* client_;

components/omnibox/browser/bookmark_provider_unittest.cc

@@ -13,7 +13,6 @@
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
-#include "base/message_loop/message_loop.h"
 #include "base/strings/string16.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_split.h"
@@ -173,7 +172,6 @@ class BookmarkProviderTest : public testing::Test {
  protected:
   void SetUp() override;
 
-  base::MessageLoop message_loop_;
   std::unique_ptr<MockAutocompleteProviderClient> provider_client_;
   std::unique_ptr<BookmarkModel> model_;
   scoped_refptr<BookmarkProvider> provider_;

components/omnibox/browser/history_url_provider_unittest.cc

@@ -13,11 +13,11 @@
 #include "base/files/scoped_temp_dir.h"
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
-#include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/test/scoped_feature_list.h"
+#include "base/test/scoped_task_environment.h"
 #include "base/time/time.h"
 #include "components/history/core/browser/history_service.h"
 #include "components/history/core/browser/url_database.h"
@@ -265,7 +265,7 @@ class HistoryURLProviderTest : public testing::Test,
                                 size_t expected_match_location,
                                 size_t expected_match_length);
 
-  base::MessageLoop message_loop_;
+  base::test::ScopedTaskEnvironment scoped_task_environment_;
   ACMatches matches_;
   std::unique_ptr<AnonFakeAutocompleteProviderClient> client_;
   scoped_refptr<HistoryURLProvider> autocomplete_;