Add a feature which, when enabled, blocks permissions after X prompt dismissals.

chrome/common/chrome_features.cc

Index: chrome/common/chrome_features.cc
diff --git a/chrome/common/chrome_features.cc b/chrome/common/chrome_features.cc
index c8317f2d2804dd5670dbf934bf91927da1c8d64b..cd34749e3103d9e6f5c205a753b22d4ed19a1a01 100644
--- a/chrome/common/chrome_features.cc
+++ b/chrome/common/chrome_features.cc
@@ -28,6 +28,11 @@ const base::Feature kBackgroundModeAllowRestart{
     "BackgroundModeAllowRestart", base::FEATURE_DISABLED_BY_DEFAULT};
 #endif  // defined(OS_WIN) || defined(OS_LINUX)
 
+// Enables or disables whether permission prompts are automatically blocked
+// after the user has explicitly dismissed them too many times.
+const base::Feature kBlockPromptsIfDismissedOften{
+    "BlockPromptsIfDismissedOften", base::FEATURE_DISABLED_BY_DEFAULT};
+
 // Experiment to disable small cross-origin content. (http://crbug.com/608886)
 const base::Feature kBlockSmallContent{"BlockSmallPluginContent",
                                        base::FEATURE_DISABLED_BY_DEFAULT};