Convert the inspector framework to use ES6 classes.

sky/framework/inspector/indexeddb-agent.sky

Index: sky/framework/inspector/indexeddb-agent.sky
diff --git a/sky/framework/inspector/indexeddb-agent.sky b/sky/framework/inspector/indexeddb-agent.sky
index 9063860f2f8b168cec188b54452f38b7e3b668e1..1aaa8b4380ee4a31b3224e06a98f445acd8e9936 100644
--- a/sky/framework/inspector/indexeddb-agent.sky
+++ b/sky/framework/inspector/indexeddb-agent.sky
@@ -1,11 +1,10 @@
 <script>
-function IndexedDB() {
+class IndexedDB {
+  // Needed to make the inspector not throw an exception.
+  requestDatabaseNames() {
+    return { "databaseNames": [] };
+  }
 }
 
-// Needed to make the inspector not throw an exception.
-IndexedDB.prototype.requestDatabaseNames = function() {
-  return { "databaseNames": [] };
-};
-
 module.exports = IndexedDB;
 </script>