Use ScopedTaskEnvironment instead of MessageLoop in /third_party/blink/renderer/platform

MessageLoop will go away, eventually.

ScopedTaskEnvironment will per default start a ThreadPool, which should
be fine in most of the cases. If you belive your test needs to make sure
that no ThreadPool runs let me know and I will update the patch.

BUG=891670
This CL was uploaded by git cl split.

R=fmalita@chromium.org

Change-Id: I19a8495c4050395219665057dd6013ec0112b643
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1649327
Auto-Submit: Carlos Caballero <carlscab@google.com>
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Florin Malita <fmalita@chromium.org>
Cr-Commit-Position: refs/heads/master@{#667125}

third_party/blink/renderer/platform/mojo/interface_invalidator_test.cc

@@ -7,9 +7,9 @@
 
 #include "base/bind.h"
 #include "base/macros.h"
-#include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "base/test/bind_test_util.h"
+#include "base/test/scoped_task_environment.h"
 #include "mojo/public/cpp/bindings/binding.h"
 #include "mojo/public/cpp/bindings/interface_ptr.h"
 #include "mojo/public/interfaces/bindings/tests/ping_service.mojom-blink.h"
@@ -97,7 +97,7 @@ class InterfaceInvalidatorTest : public testing::Test {
   ~InterfaceInvalidatorTest() override {}
 
  private:
-  base::MessageLoop message_loop_;
+  base::test::ScopedTaskEnvironment scoped_task_environment_;
 
   DISALLOW_COPY_AND_ASSIGN(InterfaceInvalidatorTest);
 };

third_party/blink/renderer/platform/mojo/kurl_security_origin_test.cc

@@ -3,7 +3,7 @@
 // found in the LICENSE file.
 
 #include "base/macros.h"
-#include "base/message_loop/message_loop.h"
+#include "base/test/scoped_task_environment.h"
 #include "mojo/public/cpp/bindings/binding.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "url/mojom/url_test.mojom-blink.h"
@@ -35,7 +35,7 @@ class UrlTestImpl : public url::mojom::blink::UrlTest {
 
 // Mojo version of chrome IPC test in url/ipc/url_param_traits_unittest.cc.
 TEST(KURLSecurityOriginStructTraitsTest, Basic) {
-  base::MessageLoop message_loop;
+  base::test::ScopedTaskEnvironment scoped_task_environment;
 
   url::mojom::blink::UrlTestPtr proxy;
   UrlTestImpl impl(MakeRequest(&proxy));

third_party/blink/renderer/platform/timer_test.cc

@@ -6,8 +6,8 @@
 
 #include <memory>
 #include <queue>
-#include "base/message_loop/message_loop.h"
 #include "base/single_thread_task_runner.h"
+#include "base/test/scoped_task_environment.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/blink/public/platform/platform.h"
@@ -83,7 +83,7 @@ class TimerTest : public testing::Test {
       platform_;
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
 
-  base::MessageLoop message_loop_;
+  base::test::ScopedTaskEnvironment scoped_task_environment_;
 };
 
 class OnHeapTimerOwner final