Add field trial param to suppress disallowed subresource notifications.

components/subresource_filter/core/browser/subresource_filter_features.h

Index: components/subresource_filter/core/browser/subresource_filter_features.h
diff --git a/components/subresource_filter/core/browser/subresource_filter_features.h b/components/subresource_filter/core/browser/subresource_filter_features.h
index 06ff4ac07c034046c73e7a31aabb4599bec63bda..4594651248f2fb8a107b6673922b5a4862b349f1 100644
--- a/components/subresource_filter/core/browser/subresource_filter_features.h
+++ b/components/subresource_filter/core/browser/subresource_filter_features.h
@@ -32,6 +32,8 @@ extern const char kActivationListPhishingInterstitial[];
 
 extern const char kPerformanceMeasurementRateParameterName[];
 
+extern const char kSuppressNotificationsParameterName[];
+
 // Returns the maximum degree to which subresource filtering should be activated
 // on any RenderFrame. This will be ActivationLevel::DISABLED unless the feature
 // is enabled and variation parameters prescribe a higher activation level.
@@ -53,6 +55,10 @@ ActivationList GetCurrentActivationList();
 // 0 unless a greater frequency is specified by variation parameters.
 double GetPerformanceMeasurementRate();
 
+// Returns whether notifications indicating that a subresource was disallowed
+// should be suppressed in the UI.
+bool ShouldSuppressNotifications();
+
 }  // namespace subresource_filter
 
 #endif  // COMPONENTS_SUBRESOURCE_FILTER_SUBRESOURCE_FILTER_FEATURES_H_