[Prerender] Get the prerender mode from Finch field trial.

chrome/browser/prerender/prerender_browsertest.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 <stddef.h>
 #include <deque>
 #include <set>
 #include <string>
 #include <unordered_map>
 #include <utility>
@@ skipping 556 matching lines @@
 
   std::vector<std::unique_ptr<TestPrerender>> PrerenderTestURL(
       const std::string& html_file,
       const std::vector<FinalStatus>& expected_final_status_queue,
       int expected_number_of_loads) {
     GURL url = src_server()->GetURL(MakeAbsolute(html_file));
     return PrerenderTestURLImpl(url, expected_final_status_queue,
                                 expected_number_of_loads);
   }
 
-  void SetUpCommandLine(base::CommandLine* command_line) override {
-    PrerenderInProcessBrowserTest::SetUpCommandLine(command_line);
-    command_line->AppendSwitchASCII(switches::kPrerenderMode,
-                                    switches::kPrerenderModeSwitchValueEnabled);
+  void SetUpOnMainThread() override {
+    test_utils::PrerenderInProcessBrowserTest::SetUpOnMainThread();
+    prerender::PrerenderManager::SetMode(
+        prerender::PrerenderManager::PRERENDER_MODE_ENABLED);
   }
 
   void SetUpInProcessBrowserTestFixture() override {
     test_utils::PrerenderInProcessBrowserTest::
         SetUpInProcessBrowserTestFixture();
 
     // Although PreferHtmlOverPlugins is redundant with the Field Trial testing
     // configuration, the official builders don't use those, so enable it here.
     feature_list_.InitAndEnableFeature(features::kPreferHtmlOverPlugins);
   }
@@ skipping 2027 matching lines @@
  public:
   PrerenderBrowserTestWithExtensions() {
     // The individual tests start the test server through ExtensionApiTest, so
     // the port number can be passed through to the extension.
     set_autostart_test_server(false);
   }
 
   void SetUp() override { PrerenderBrowserTest::SetUp(); }
 
   void SetUpCommandLine(base::CommandLine* command_line) override {
-    PrerenderBrowserTest::SetUpCommandLine(command_line);
     ExtensionApiTest::SetUpCommandLine(command_line);
   }
 
   void SetUpInProcessBrowserTestFixture() override {
     PrerenderBrowserTest::SetUpInProcessBrowserTestFixture();
     ExtensionApiTest::SetUpInProcessBrowserTestFixture();
   }
 
   void TearDownInProcessBrowserTestFixture() override {
     PrerenderBrowserTest::TearDownInProcessBrowserTestFixture();
@@ skipping 651 matching lines @@
 }
 
 // Can't run tests with NaCl plugins if built with DISABLE_NACL.
 #if !defined(DISABLE_NACL)
 class PrerenderBrowserTestWithNaCl : public PrerenderBrowserTest {
  public:
   PrerenderBrowserTestWithNaCl() {}
   ~PrerenderBrowserTestWithNaCl() override {}
 
   void SetUpCommandLine(base::CommandLine* command_line) override {
-    PrerenderBrowserTest::SetUpCommandLine(command_line);
     command_line->AppendSwitch(switches::kEnableNaCl);
   }
 };
 
 // PrerenderNaClPluginEnabled crashes on ARM: http://crbug.com/585251
 #if defined(ARCH_CPU_ARM_FAMILY)
 #define MAYBE_PrerenderNaClPluginEnabled DISABLED_PrerenderNaClPluginEnabled
 #else
 #define MAYBE_PrerenderNaClPluginEnabled PrerenderNaClPluginEnabled
 #endif
@@ skipping 11 matching lines @@
       browser()->tab_strip_model()->GetActiveWebContents();
   bool display_test_result = false;
   ASSERT_TRUE(content::ExecuteScriptAndExtractBool(web_contents,
                                                    "DidDisplayReallyPass()",
                                                    &display_test_result));
   ASSERT_TRUE(display_test_result);
 }
 #endif  // !defined(DISABLE_NACL)
 
 }  // namespace prerender