Extensions: Pull duplicated functionality into ExtensionsTest fixture.

content/public/test/test_browser_context.cc

Index: content/public/test/test_browser_context.cc
diff --git a/content/public/test/test_browser_context.cc b/content/public/test/test_browser_context.cc
index 0929df4e0023835d6b22d316409d0d4ef8580042..44a965ab16edb20ce573ca5474379f84cc880d77 100644
--- a/content/public/test/test_browser_context.cc
+++ b/content/public/test/test_browser_context.cc
@@ -74,6 +74,10 @@ net::URLRequestContextGetter* TestBrowserContext::GetRequestContext() {
   return request_context_.get();
 }
 
+void TestBrowserContext::SetOffTheRecord(bool is_off_the_record) {
+  is_off_the_record_ = is_off_the_record;
+}
+
 base::FilePath TestBrowserContext::GetPath() const {
   return browser_context_dir_.GetPath();
 }
@@ -84,7 +88,7 @@ std::unique_ptr<ZoomLevelDelegate> TestBrowserContext::CreateZoomLevelDelegate(
 }
 
 bool TestBrowserContext::IsOffTheRecord() const {
-  return false;
+  return is_off_the_record_;
 }
 
 DownloadManagerDelegate* TestBrowserContext::GetDownloadManagerDelegate() {