Implement RevokePermission() method in PermissionService.

content/public/browser/content_browser_client.cc

Index: content/public/browser/content_browser_client.cc
diff --git a/content/public/browser/content_browser_client.cc b/content/public/browser/content_browser_client.cc
index 91c8a4dbbf4e3743df75eae6c11238cc86334354..51bc6ae03e4ffe5adb8221c9507b792739db99aa 100644
--- a/content/public/browser/content_browser_client.cc
+++ b/content/public/browser/content_browser_client.cc
@@ -242,6 +242,14 @@ PermissionStatus ContentBrowserClient::GetPermissionStatus(
   return PERMISSION_STATUS_DENIED;
 }
 
+PermissionStatus ContentBrowserClient::RevokePermission(
+    PermissionType permission,
+    BrowserContext* browser_context,
+    const GURL& requesting_origin,
+    const GURL& embedding_origin) {
+  return PERMISSION_STATUS_ASK;
+}
+
 bool ContentBrowserClient::CanCreateWindow(
     const GURL& opener_url,
     const GURL& opener_top_level_frame_url,