Create only one ContextFactory in content unit tests

content/browser/renderer_host/render_widget_host_view_aura_unittest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/renderer_host/render_widget_host_view_aura.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <tuple>
@@ skipping 3837 matching lines @@
 // a WebContents instance.
 class RenderWidgetHostViewAuraWithViewHarnessTest
     : public RenderViewHostImplTestHarness {
  public:
    RenderWidgetHostViewAuraWithViewHarnessTest()
       : view_(nullptr) {}
    ~RenderWidgetHostViewAuraWithViewHarnessTest() override {}
 
  protected:
   void SetUp() override {
-    ImageTransportFactory::InitializeForUnitTests(
-        std::unique_ptr<ImageTransportFactory>(
-            new NoTransportImageTransportFactory));
     RenderViewHostImplTestHarness::SetUp();
     // Delete the current RenderWidgetHostView instance before setting
     // the RWHVA as the view.
     delete contents()->GetRenderViewHost()->GetWidget()->GetView();
     // This instance is destroyed in the TearDown method below.
     view_ = new RenderWidgetHostViewAura(
         contents()->GetRenderViewHost()->GetWidget(),
         false);
   }
 
   void TearDown() override {
     view_->Destroy();
     RenderViewHostImplTestHarness::TearDown();
-    ImageTransportFactory::Terminate();
   }
 
   RenderWidgetHostViewAura* view() {
     return view_;
   }
 
  private:
   RenderWidgetHostViewAura* view_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostViewAuraWithViewHarnessTest);
@@ skipping 107 matching lines @@
   view()->OnGestureEvent(&gesture_event);
 
   EXPECT_TRUE(delegate->context_menu_request_received());
   EXPECT_EQ(delegate->context_menu_source_type(), ui::MENU_SOURCE_TOUCH);
 #endif
 
   RenderViewHostFactory::set_is_real_render_view_host(false);
 }
 
 }  // namespace content