Remove direct usage of BrowserThreadImpl in tests

content/browser/renderer_host/render_widget_host_unittest.cc

Index: content/browser/renderer_host/render_widget_host_unittest.cc
diff --git a/content/browser/renderer_host/render_widget_host_unittest.cc b/content/browser/renderer_host/render_widget_host_unittest.cc
index 75185179fd9fb39db99a7f5cad1aecaac6f85424..3b1d1c5195ca17aadbc82fa0fa905d7a22bbb7c1 100644
--- a/content/browser/renderer_host/render_widget_host_unittest.cc
+++ b/content/browser/renderer_host/render_widget_host_unittest.cc
@@ -17,7 +17,6 @@
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/timer/timer.h"
 #include "build/build_config.h"
-#include "content/browser/browser_thread_impl.h"
 #include "content/browser/gpu/compositor_util.h"
 #include "content/browser/renderer_host/input/input_router_impl.h"
 #include "content/browser/renderer_host/render_widget_host_delegate.h"
@@ -29,6 +28,7 @@
 #include "content/public/common/content_switches.h"
 #include "content/public/test/mock_render_process_host.h"
 #include "content/public/test/test_browser_context.h"
+#include "content/public/test/test_browser_thread_bundle.h"
 #include "content/test/test_render_view_host.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/display/screen.h"
@@ -641,8 +641,6 @@ class RenderWidgetHostTest : public testing::Test {
     return reinterpret_cast<const WebInputEvent*>(data);
   }
 
-  base::MessageLoopForUI message_loop_;
-
   std::unique_ptr<TestBrowserContext> browser_context_;
   RenderWidgetHostProcess* process_;  // Deleted automatically by the widget.
   std::unique_ptr<MockRenderWidgetHostDelegate> delegate_;
@@ -661,6 +659,8 @@ class RenderWidgetHostTest : public testing::Test {
  private:
   SyntheticWebTouchEvent touch_event_;
 
+  TestBrowserThreadBundle thread_bundle_;
+
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostTest);
 };
 
@@ -896,7 +896,6 @@ TEST_F(RenderWidgetHostTest, Background) {
 // Test that we don't paint when we're hidden, but we still send the ACK. Most
 // of the rest of the painting is tested in the GetBackingStore* ones.
 TEST_F(RenderWidgetHostTest, HiddenPaint) {
-  BrowserThreadImpl ui_thread(BrowserThread::UI, base::MessageLoop::current());
   // Hide the widget, it should have sent out a message to the renderer.
   EXPECT_FALSE(host_->is_hidden_);
   host_->WasHidden();