Add Physical Web experiment and command line flags

ios/chrome/browser/experimental_flags.mm

 // 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.
 
 // This file can be empty. Its purpose is to contain the relatively short lived
 // definitions required for experimental flags.
 
 #include "ios/chrome/browser/experimental_flags.h"
 
 #include <dispatch/dispatch.h>
@@ skipping 103 matching lines @@
   std::string group_name =
       base::FieldTrialList::FindFullName("RemoveAllBookmarks");
 
   if (group_name.empty()) {
     return true;  // If no finch experiment, keep all bookmarks enabled.
   }
   return base::StartsWith(group_name, "Enabled",
                           base::CompareCase::INSENSITIVE_ASCII);
 }
 
+bool IsPhysicalWebEnabled() {
+  base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();

[Olivier, 2016/06/24 07:52:33]

I think you should check for the NSUserDefault to check for the experimental
flags in settings.

[mattreynolds, 2016/06/24 17:47:20]

I think this is unnecessary because in about_flags.mm we append command line
switches for the default values.  I tried to follow the same pattern used by the
AllBookmarks switch above.

+  if (command_line->HasSwitch(switches::kEnableIOSPhysicalWeb)) {
+    return true;
+  } else if (command_line->HasSwitch(switches::kDisableIOSPhysicalWeb)) {
+    return false;
+  }
+
+  // Check if the finch experiment is turned on
+  std::string group_name =
+      base::FieldTrialList::FindFullName("PhysicalWebEnabled");
+  return base::StartsWith(group_name, "Enabled",
+                          base::CompareCase::INSENSITIVE_ASCII);
+}
+
 }  // namespace experimental_flags