Switch content tests to use BrowserThreadImpl directly.

content/browser/plugin_loader_posix_unittest.cc

Index: content/browser/plugin_loader_posix_unittest.cc
diff --git a/content/browser/plugin_loader_posix_unittest.cc b/content/browser/plugin_loader_posix_unittest.cc
index d92eee00b7c279b73b558a36794817a1434b4d12..1ed408024cd5dc5eae6123c4b5db5e9baf666d60 100644
--- a/content/browser/plugin_loader_posix_unittest.cc
+++ b/content/browser/plugin_loader_posix_unittest.cc
@@ -9,11 +9,13 @@
 #include "base/memory/ref_counted.h"
 #include "base/message_loop.h"
 #include "base/utf_string_conversions.h"
-#include "content/test/test_browser_thread.h"
+#include "content/browser/browser_thread_impl.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "webkit/plugins/webplugininfo.h"
 
+using content::BrowserThreadImpl;
+
 class MockPluginLoaderPosix : public PluginLoaderPosix {
  public:
   MOCK_METHOD0(LoadPluginsInternal, void(void));
@@ -82,8 +84,8 @@ class PluginLoaderPosixTest : public testing::Test {
 
  private:
   MessageLoopForIO message_loop_;
-  content::TestBrowserThread file_thread_;
-  content::TestBrowserThread io_thread_;
+  BrowserThreadImpl file_thread_;
+  BrowserThreadImpl io_thread_;
 
   scoped_refptr<MockPluginLoaderPosix> plugin_loader_;
 };