Add Physical Web experiment and command line flags

ios/chrome/browser/experimental_flags.mm

Index: ios/chrome/browser/experimental_flags.mm
diff --git a/ios/chrome/browser/experimental_flags.mm b/ios/chrome/browser/experimental_flags.mm
index 1081ddd752fcbbd8eadbe1520658aea7e5ed58e3..5e6be562c46df578d8abf208c01bef8ee9a0e692 100644
--- a/ios/chrome/browser/experimental_flags.mm
+++ b/ios/chrome/browser/experimental_flags.mm
@@ -121,4 +121,19 @@ bool IsAllBookmarksEnabled() {
                           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