bindings: Makes almost all attributes accessor-type properties.

Source/modules/cachestorage/WorkerCacheStorage.idl

Index: Source/modules/cachestorage/WorkerCacheStorage.idl
diff --git a/Source/modules/cachestorage/WorkerCacheStorage.idl b/Source/modules/cachestorage/WorkerCacheStorage.idl
index 483f3992a507e6d7ac45fe9c5e8ffa93b540d9db..01e23b12179560425143d1f6f96b61da661baeae 100644
--- a/Source/modules/cachestorage/WorkerCacheStorage.idl
+++ b/Source/modules/cachestorage/WorkerCacheStorage.idl
@@ -7,5 +7,11 @@
     RuntimeEnabled=GlobalCacheStorage,
     ImplementedAs=GlobalCacheStorage,
 ] partial interface WorkerGlobalScope {
-  [Unforgeable, MeasureAs=GlobalCacheStorage, RuntimeEnabled=GlobalCacheStorage, RaisesException] readonly attribute CacheStorage caches;
+    // Inheritance of [Unforgeable] attributes is not supported.  So we have to
+    // define the same unforgeable attributes in derived interfaces as well.
+    // See that {,Dedicated,Shared,Compositor,Service}WorkerGlobalScope redefine
+    // 'caches' attribute.
+    // Keep all the definitions consistent.
+    // TODO(yukishiino): Support inheritance of attributes defined on instance.
+    [Unforgeable, MeasureAs=GlobalCacheStorage, RuntimeEnabled=GlobalCacheStorage, RaisesException] readonly attribute CacheStorage caches;
 };