Make DETECT_IMPORTANT_CONTENT the default Plugins content setting based

chrome/browser/plugins/plugins_field_trial_browsertest.cc

+// Copyright 2015 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 "components/content_settings/core/browser/plugins_field_trial.h"
+
+#include "base/command_line.h"
+#include "base/macros.h"
+#include "base/prefs/pref_service.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/ui/browser.h"
+#include "chrome/test/base/in_process_browser_test.h"
+#include "components/content_settings/core/common/content_settings.h"
+#include "components/content_settings/core/common/pref_names.h"
+#include "content/public/common/content_switches.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+using content_settings::PluginsFieldTrial;
+
+class PluginsFieldTrialPrefTest : public InProcessBrowserTest {
+ public:
+  PluginsFieldTrialPrefTest() {}
+  ~PluginsFieldTrialPrefTest() override {}
+
+  void SetUpCommandLine(base::CommandLine* cli) override {
+    InProcessBrowserTest::SetUpCommandLine(cli);
+    std::string forced_field_trials(PluginsFieldTrial::kFieldTrialName);
+    forced_field_trials += "/Enabled/";
+    cli->AppendSwitchASCII(switches::kForceFieldTrials, forced_field_trials);
+  }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(PluginsFieldTrialPrefTest);
+};
+
+IN_PROC_BROWSER_TEST_F(PluginsFieldTrialPrefTest, EnableFieldTrialNoPrefSet) {
+  const PrefService* prefs = browser()->profile()->GetPrefs();
+  EXPECT_EQ(CONTENT_SETTING_DETECT_IMPORTANT_CONTENT,
+            prefs->GetInteger(prefs::kDefaultPluginsSetting));
+  EXPECT_FALSE(prefs->HasPrefPath(prefs::kDefaultPluginsSetting));
+}