[Win] Add a fast profile switcher to the Windows taskbar item.

components/signin/core/common/profile_management_switches.cc

Index: components/signin/core/common/profile_management_switches.cc
diff --git a/components/signin/core/common/profile_management_switches.cc b/components/signin/core/common/profile_management_switches.cc
index f1a72033047ef77805873b79354742d2eb954671..f02aa3dda84d62e51b928ac906db2acd20bcb289 100644
--- a/components/signin/core/common/profile_management_switches.cc
+++ b/components/signin/core/common/profile_management_switches.cc
@@ -187,4 +187,10 @@ void EnableAccountConsistencyForTesting(base::CommandLine* command_line) {
   DCHECK(!command_line->HasSwitch(switches::kDisableAccountConsistency));
 }
 
+bool HasProfilesJumplistExperiment() {
+  const std::string group_name =
+      base::FieldTrialList::FindFullName("Windows-Jumplist-Profiles");
+  return group_name == "Use-Profiles";
+}
+
 }  // namespace switches