[headless] Remove default browser context.

headless/test/headless_browser_test.h

Index: headless/test/headless_browser_test.h
diff --git a/headless/test/headless_browser_test.h b/headless/test/headless_browser_test.h
index 8189d50cf6286384d2e105386ce4b4a709de0e7e..3ed1fb18a6eb646053fdc43ccc8dc0a819b47ceb 100644
--- a/headless/test/headless_browser_test.h
+++ b/headless/test/headless_browser_test.h
@@ -64,11 +64,6 @@ class HeadlessBrowserTest : public content::BrowserTestBase {
   void SetUpOnMainThread() override;
   void TearDownOnMainThread() override;
 
-  // Customize the options used in this test. Note that options which take
-  // effect before the message loop has been started (e.g., custom message
-  // pumps) cannot be set via this method.
-  void SetBrowserOptions(HeadlessBrowser::Options options);
-
   // Run an asynchronous test in a nested run loop. The caller should call
   // FinishAsynchronousTest() to notify that the test should finish.
   void RunAsynchronousTest();
@@ -115,6 +110,7 @@ class HeadlessAsyncDevTooledBrowserTest : public HeadlessBrowserTest,
  protected:
   void RunTest();
 
+  std::unique_ptr<HeadlessBrowserContext> browser_context_;
   HeadlessWebContents* web_contents_;
   std::unique_ptr<HeadlessDevToolsClient> devtools_client_;
 };