[Android] Adding content settings provider for notification channels

components/content_settings/core/browser/host_content_settings_map.cc

Index: components/content_settings/core/browser/host_content_settings_map.cc
diff --git a/components/content_settings/core/browser/host_content_settings_map.cc b/components/content_settings/core/browser/host_content_settings_map.cc
index 52a6708ea74cd789da27059c168cb63c4776712f..92c7e2a322c3fb6d6fb80885a36d9bb6fa7d5ca9 100644
--- a/components/content_settings/core/browser/host_content_settings_map.cc
+++ b/components/content_settings/core/browser/host_content_settings_map.cc
@@ -55,6 +55,7 @@ const ProviderNamesSourceMapEntry kProviderNamesSourceMap[] = {
     {"policy", content_settings::SETTING_SOURCE_POLICY},
     {"supervised_user", content_settings::SETTING_SOURCE_SUPERVISED},
     {"extension", content_settings::SETTING_SOURCE_EXTENSION},
+    {"notification_android", content_settings::SETTING_SOURCE_USER},
     {"preference", content_settings::SETTING_SOURCE_USER},
     {"default", content_settings::SETTING_SOURCE_USER},
 };
@@ -384,6 +385,8 @@ void HostContentSettingsMap::SetWebsiteSettingCustomScope(
     std::unique_ptr<base::Value> value) {
   DCHECK(SupportsResourceIdentifier(content_type) ||
          resource_identifier.empty());
+  // TODO(crbug.com/731126): Verify that assumptions for notification content
+  // settings are met.
   UsedContentSettingsProviders();
 
   for (const auto& provider_pair : content_settings_providers_) {
@@ -910,4 +913,4 @@ HostContentSettingsMap::GetContentSettingValueAndPatterns(
 void HostContentSettingsMap::SetClockForTesting(
     std::unique_ptr<base::Clock> clock) {
   pref_provider_->SetClockForTesting(std::move(clock));
-}
+}