Set up Finch feature for network time policy browser test

chrome/browser/policy/policy_browsertest.cc

Index: chrome/browser/policy/policy_browsertest.cc
diff --git a/chrome/browser/policy/policy_browsertest.cc b/chrome/browser/policy/policy_browsertest.cc
index 177bea75fd1be10b112d622e3d0c4e1eb1f3b32e..b7eae5b09e3c2d98db01f0ecb4b6be7d62967773 100644
--- a/chrome/browser/policy/policy_browsertest.cc
+++ b/chrome/browser/policy/policy_browsertest.cc
@@ -12,6 +12,7 @@
 #include <vector>
 
 #include "ash/accelerators/accelerator_controller_delegate_aura.h"
+#include "base/base_switches.h"
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/callback.h"
@@ -132,6 +133,7 @@
 #include "components/update_client/url_request_post_interceptor.h"
 #include "components/user_prefs/user_prefs.h"
 #include "components/variations/service/variations_service.h"
+#include "components/variations/variations_switches.h"
 #include "components/version_info/version_info.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/browser_thread.h"
@@ -4506,6 +4508,20 @@ IN_PROC_BROWSER_TEST_F(ChromeOSPolicyTest, SystemTimezoneAutomaticDetection) {
 
 class NetworkTimePolicyTest : public PolicyTest {
  public:
+  void SetUpCommandLine(base::CommandLine* command_line) override {
+    command_line->AppendSwitchASCII(
+        switches::kEnableFeatures,
+        std::string(network_time::kNetworkTimeServiceQuerying.name) +
+            "<SSLNetworkTimeBrowserTestFieldTrial");

[Nico, 2017/05/24 17:43:03]

The < here is intentional, yes?

[estark, 2017/05/24 17:45:17]

Yeah, it's the --enable-features syntax (it's "GroupName>TrialName" or something
like that.)

Btw, I tested this by fix by removing the field trial from
fieldtrial_testing_config.json, observing that the test as I originally wrote it
failed, then observing that it passed with this SetUpCommandLine impl.

+    command_line->AppendSwitchASCII(
+        switches::kForceFieldTrials,
+        "SSLNetworkTimeBrowserTestFieldTrial/Enabled/");
+    command_line->AppendSwitchASCII(
+        variations::switches::kForceFieldTrialParams,
+        "SSLNetworkTimeBrowserTestFieldTrial.Enabled:FetchBehavior/"
+        "on-demand-only");
+  }
+
   // A request handler that returns a dummy response and counts the number of
   // times it is called.
   std::unique_ptr<net::test_server::HttpResponse> CountingRequestHandler(