Revert of Adding task runner/ message loop to tests that use IsolateHolder.

content/test/test_blink_web_unit_test_support.cc

Index: content/test/test_blink_web_unit_test_support.cc
diff --git a/content/test/test_blink_web_unit_test_support.cc b/content/test/test_blink_web_unit_test_support.cc
index 8aa66187af66a49145d8a2c25588f18685f18ad4..7405be6f417d040cb42b0292c52396f86b370043 100644
--- a/content/test/test_blink_web_unit_test_support.cc
+++ b/content/test/test_blink_web_unit_test_support.cc
@@ -8,10 +8,7 @@
 #include "base/files/file_util.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/path_service.h"
-#include "base/single_thread_task_runner.h"
 #include "base/strings/utf_string_conversions.h"
-#include "base/thread_task_runner_handle.h"
-#include "base/threading/platform_thread.h"
 #include "components/scheduler/renderer/renderer_scheduler.h"
 #include "components/scheduler/renderer/webthread_impl_for_renderer_scheduler.h"
 #include "content/test/mock_webclipboard_impl.h"
@@ -44,40 +41,6 @@
 #include "gin/v8_initializer.h"
 #endif
 
-namespace {
-
-class DummyTaskRunner : public base::SingleThreadTaskRunner {
- public:
-  DummyTaskRunner() : thread_id_(base::PlatformThread::CurrentId()) {}
-
-  bool PostDelayedTask(const tracked_objects::Location& from_here,
-                       const base::Closure& task,
-                       base::TimeDelta delay) override {
-    NOTREACHED();
-    return false;
-  }
-
-  bool PostNonNestableDelayedTask(const tracked_objects::Location& from_here,
-                                  const base::Closure& task,
-                                  base::TimeDelta delay) override {
-    NOTREACHED();
-    return false;
-  }
-
-  bool RunsTasksOnCurrentThread() const override {
-    return thread_id_ == base::PlatformThread::CurrentId();
-  }
-
- protected:
-  ~DummyTaskRunner() override {}
-
-  base::PlatformThreadId thread_id_;
-
-  DISALLOW_COPY_AND_ASSIGN(DummyTaskRunner);
-};
-
-}  // namespace
-
 namespace content {
 
 TestBlinkWebUnitTestSupport::TestBlinkWebUnitTestSupport() {
@@ -92,23 +55,10 @@
   gin::V8Initializer::LoadV8Snapshot();
 #endif
 
-  scoped_refptr<base::SingleThreadTaskRunner> dummy_task_runner;
-  scoped_ptr<base::ThreadTaskRunnerHandle> dummy_task_runner_handle;
   if (base::MessageLoopProxy::current()) {
     renderer_scheduler_ = scheduler::RendererScheduler::Create();
     web_thread_.reset(new scheduler::WebThreadImplForRendererScheduler(
         renderer_scheduler_.get()));
-  } else {
-    // Dummy task runner is initialized here because the blink::initialize
-    // creates IsolateHolder which needs the current task runner handle. There
-    // should be no task posted to this task runner. The message loop is not
-    // created before this initialization because some tests need specific kinds
-    // of message loops, and their types are not known upfront. Some tests also
-    // create their own thread bundles or message loops, and doing the same in
-    // TestBlinkWebUnitTestSupport would introduce a conflict.
-    dummy_task_runner = make_scoped_refptr(new DummyTaskRunner());
-    dummy_task_runner_handle.reset(
-        new base::ThreadTaskRunnerHandle(dummy_task_runner));
   }
 
   blink::initialize(this);