2 files changed, 33 insertions, 7 deletions
diff --git a/chrome/browser/content_settings/host_content_settings_map.cc b/chrome/browser/content_settings/host_content_settings_map.cc
index 421f0c1..50606ad 100644
--- a/chrome/browser/content_settings/host_content_settings_map.cc
+++ b/chrome/browser/content_settings/host_content_settings_map.cc
@@ -77,8 +77,11 @@ bool SupportsResourceIdentifier(ContentSettingsType content_type) {
 
 HostContentSettingsMap::HostContentSettingsMap(
     PrefService* prefs,
-    bool incognito)
-    : prefs_(prefs),
+    bool incognito) :
+#ifndef NDEBUG
+      used_content_settings_providers_(false),
+#endif
+      prefs_(prefs),
       is_off_the_record_(incognito) {
   content_settings::ObservableProvider* policy_provider =
       new content_settings::PolicyProvider(prefs_);
@@ -105,6 +108,9 @@ HostContentSettingsMap::HostContentSettingsMap(
 void HostContentSettingsMap::RegisterExtensionService(
     ExtensionService* extension_service) {
   DCHECK(extension_service);
+#ifndef NDEBUG
+  DCHECK(!used_content_settings_providers_);
+#endif
   DCHECK(!content_settings_providers_[INTERNAL_EXTENSION_PROVIDER]);
   DCHECK(!content_settings_providers_[CUSTOM_EXTENSION_PROVIDER]);
 
@@ -167,6 +173,8 @@ ContentSetting HostContentSettingsMap::GetDefaultContentSettingFromProvider(
 ContentSetting HostContentSettingsMap::GetDefaultContentSetting(
     ContentSettingsType content_type,
     std::string* provider_id) const {
+  UsedContentSettingsProviders();
+
   // Iterate through the list of providers and return the first non-NULL value
   // that matches |primary_url| and |secondary_url|.
   for (ConstProviderIterator provider = content_settings_providers_.begin();
@@ -208,6 +216,7 @@ void HostContentSettingsMap::GetSettingsForOneType(
   DCHECK(SupportsResourceIdentifier(content_type) ||
          resource_identifier.empty());
   DCHECK(settings);
+  UsedContentSettingsProviders();
 
   settings->clear();
   for (ConstProviderIterator provider = content_settings_providers_.begin();
@@ -257,6 +266,8 @@ void HostContentSettingsMap::SetWebsiteSetting(
   DCHECK(IsValueAllowedForType(prefs_, value, content_type));
   DCHECK(SupportsResourceIdentifier(content_type) ||
          resource_identifier.empty());
+  UsedContentSettingsProviders();
+
   for (ProviderIterator provider = content_settings_providers_.begin();
        provider != content_settings_providers_.end();
        ++provider) {
@@ -316,6 +327,7 @@ void HostContentSettingsMap::AddExceptionForURL(
 
 void HostContentSettingsMap::ClearSettingsForOneType(
     ContentSettingsType content_type) {
+  UsedContentSettingsProviders();
   for (ProviderIterator provider = content_settings_providers_.begin();
        provider != content_settings_providers_.end();
        ++provider) {
@@ -497,6 +509,12 @@ void HostContentSettingsMap::AddSettingsForOneType(
   }
 }
 
+void HostContentSettingsMap::UsedContentSettingsProviders() const {
+#ifndef NDEBUG
+  used_content_settings_providers_ = true;
+#endif
+}
+
 bool HostContentSettingsMap::ShouldAllowAllContent(
     const GURL& primary_url,
     const GURL& secondary_url,
diff --git a/chrome/browser/content_settings/host_content_settings_map.h b/chrome/browser/content_settings/host_content_settings_map.h
index 635a3db..46f62ff 100644
--- a/chrome/browser/content_settings/host_content_settings_map.h
+++ b/chrome/browser/content_settings/host_content_settings_map.h
@@ -15,7 +15,6 @@
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
 #include "base/prefs/public/pref_change_registrar.h"
-#include "base/synchronization/lock.h"
 #include "base/tuple.h"
 #include "chrome/browser/content_settings/content_settings_observer.h"
 #include "chrome/common/content_settings.h"
@@ -230,18 +229,27 @@ class HostContentSettingsMap
       ContentSettingsForOneType* settings,
       bool incognito) const;
 
+  // Call UsedContentSettingsProviders() whenever you access
+  // content_settings_providers_ (apart from initialization and
+  // teardown), so that we can DCHECK in RegisterExtensionService that
+  // it is not being called too late.
+  void UsedContentSettingsProviders() const;
+
+#ifndef NDEBUG
+  mutable bool used_content_settings_providers_;
+#endif
+
   // Weak; owned by the Profile.
   PrefService* prefs_;
 
   // Whether this settings map is for an OTR session.
   bool is_off_the_record_;
 
-  // Content setting providers.
+  // Content setting providers. This is only modified at construction
+  // time and by RegisterExtensionService, both of which should happen
+  // before any other uses of it.
   ProviderMap content_settings_providers_;
 
-  // Used around accesses to the following objects to guarantee thread safety.
-  mutable base::Lock lock_;
-
   DISALLOW_COPY_AND_ASSIGN(HostContentSettingsMap);
 };