Using PolicyServiceWatcher instead of PolicyWatcherLinux/Win/Mac.

components/policy/core/common/policy_service_impl.cc

Index: components/policy/core/common/policy_service_impl.cc
diff --git a/components/policy/core/common/policy_service_impl.cc b/components/policy/core/common/policy_service_impl.cc
index d515d1923da2877cd06551d7f7d16b9ca7bfe9e4..9d022b05fd1e42dd00e694524d53b6c4ba74682c 100644
--- a/components/policy/core/common/policy_service_impl.cc
+++ b/components/policy/core/common/policy_service_impl.cc
@@ -88,6 +88,7 @@ PolicyServiceImpl::PolicyServiceImpl(const Providers& providers)
 }
 
 PolicyServiceImpl::~PolicyServiceImpl() {
+  DCHECK(thread_checker_.CalledOnValidThread());
   for (Iterator it = providers_.begin(); it != providers_.end(); ++it)
     (*it)->RemoveObserver(this);
   STLDeleteValues(&observers_);
@@ -95,6 +96,7 @@ PolicyServiceImpl::~PolicyServiceImpl() {
 
 void PolicyServiceImpl::AddObserver(PolicyDomain domain,
                                     PolicyService::Observer* observer) {
+  DCHECK(thread_checker_.CalledOnValidThread());
   Observers*& list = observers_[domain];
   if (!list)
     list = new Observers();
@@ -103,6 +105,7 @@ void PolicyServiceImpl::AddObserver(PolicyDomain domain,
 
 void PolicyServiceImpl::RemoveObserver(PolicyDomain domain,
                                        PolicyService::Observer* observer) {
+  DCHECK(thread_checker_.CalledOnValidThread());
   ObserverMap::iterator it = observers_.find(domain);
   if (it == observers_.end()) {
     NOTREACHED();
@@ -170,6 +173,7 @@ void PolicyServiceImpl::NotifyNamespaceUpdated(
     const PolicyNamespace& ns,
     const PolicyMap& previous,
     const PolicyMap& current) {
+  DCHECK(thread_checker_.CalledOnValidThread());
   ObserverMap::iterator iterator = observers_.find(ns.domain);
   if (iterator != observers_.end()) {
     FOR_EACH_OBSERVER(PolicyService::Observer,
@@ -231,6 +235,8 @@ void PolicyServiceImpl::MergeAndTriggerUpdates() {
 }
 
 void PolicyServiceImpl::CheckInitializationComplete() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
   // Check if all the providers just became initialized for each domain; if so,
   // notify that domain's observers.
   for (int domain = 0; domain < POLICY_DOMAIN_SIZE; ++domain) {