Re-fix http://crbug.com/87176, and add a test.

content/browser/renderer_host/media/web_contents_video_capture_device_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/media/web_contents_video_capture_device.h"
 
 #include "base/bind_helpers.h"
 #include "base/debug/debugger.h"
 #include "base/run_loop.h"
 #include "base/test/test_timeouts.h"
@@ skipping 429 matching lines @@
     render_process_host_factory_.reset(new MockRenderProcessHostFactory());
     // Create our (self-registering) RVH factory, so that when we create a
     // WebContents, it in turn creates CaptureTestRenderViewHosts.
     render_view_host_factory_.reset(
         new CaptureTestRenderViewHostFactory(&controller_));
 
     browser_context_.reset(new TestBrowserContext());
 
     scoped_refptr<SiteInstance> site_instance =
         SiteInstance::Create(browser_context_.get());
-    static_cast<SiteInstanceImpl*>(site_instance.get())->
-        set_render_process_host_factory(render_process_host_factory_.get());
+    SiteInstanceImpl::set_render_process_host_factory(
+        render_process_host_factory_.get());
     web_contents_.reset(
         TestWebContents::Create(browser_context_.get(), site_instance.get()));
 
     // This is actually a CaptureTestRenderViewHost.
     RenderWidgetHostImpl* rwh =
         RenderWidgetHostImpl::From(web_contents_->GetRenderViewHost());
 
     std::string device_id =
         WebContentsCaptureUtil::AppendWebContentsDeviceScheme(
             base::StringPrintf("%d:%d", rwh->GetProcess()->GetID(),
@@ skipping 16 matching lines @@
     }
 
     content::RunAllPendingInMessageLoop();
 
     // Destroy the browser objects.
     web_contents_.reset();
     browser_context_.reset();
 
     content::RunAllPendingInMessageLoop();
 
+    SiteInstanceImpl::set_render_process_host_factory(NULL);
     render_view_host_factory_.reset();
     render_process_host_factory_.reset();
   }
 
   // Accessors.
   CaptureTestSourceController* source() { return &controller_; }
   media::VideoCaptureDevice* device() { return device_.get(); }
   StubConsumer* consumer() { return &consumer_; }
 
   void SimulateDrawEvent() {
@@ skipping 227 matching lines @@
   ASSERT_NO_FATAL_FAILURE(consumer()->WaitForNextColor(SK_ColorGREEN));
   source()->SetSolidColor(SK_ColorRED);
   ASSERT_NO_FATAL_FAILURE(consumer()->WaitForNextColor(SK_ColorRED));
 
   device()->Stop();
   device()->DeAllocate();
 }
 
 }  // namespace
 }  // namespace content