[ServiceWorker] Implement Headers class.

Source/modules/serviceworkers/Headers.idl

Index: Source/modules/serviceworkers/Headers.idl
diff --git a/Source/modules/serviceworkers/HeaderMap.idl b/Source/modules/serviceworkers/Headers.idl
similarity index 28%
copy from Source/modules/serviceworkers/HeaderMap.idl
copy to Source/modules/serviceworkers/Headers.idl
index 38d198bda48eda69952f48a42f53e83ef8f72fd0..ad662b041327760603bd64417fda7a18f48a0880 100644
--- a/Source/modules/serviceworkers/HeaderMap.idl
+++ b/Source/modules/serviceworkers/Headers.idl
@@ -3,26 +3,23 @@
 // found in the LICENSE file.
 
 // http://fetch.spec.whatwg.org/#headers-class
-// FIXME: Fetch spec has renamed this to just 'Headers'
-// FIXME: This should be defined as MapClass(DOMString, DOMString)
-// once binding code supports it (http://crbug.com/347435).
 [
     Constructor,
+    Constructor(Headers input),
+    Constructor(Dictionary input),
     RuntimeEnabled=ServiceWorker,
-    Exposed=ServiceWorker
-] interface HeaderMap {
-    readonly attribute unsigned long size;
-
-    // FIXME: Define keys, values, entries.
-    // FIXME: Some of the method definitions (like set) don't strictly
-    // follow the MapClass's ones (http://heycam.github.io/webidl/#MapClass),
-    // as this is supposed to be a transient implementation until we have real
-    // MapClass.
+    Exposed=ServiceWorker,
+    RaisesException=Constructor
+] interface Headers {
+    [RaisesException] void append(ByteString name, ByteString value);
+    [ImplementedAs=remove, RaisesException] void delete(ByteString key);
+    [TreatReturnedNullStringAs=Null, RaisesException] ByteString? get(ByteString key);
+    [RaisesException] sequence<ByteString> getAll(ByteString name);
+    [RaisesException] boolean has(ByteString key);
+    [RaisesException] void set(ByteString key, ByteString value);
 
-    void clear();
-    [ImplementedAs=remove] boolean delete(DOMString key);
-    DOMString get(DOMString key);
-    boolean has(DOMString key);
-    void set(DOMString key, DOMString value);
-    void forEach(HeaderMapForEachCallback callback, optional any thisArg);
+    // The followings are not defined in the spec yet.
+    // https://www.w3.org/Bugs/Public/show_bug.cgi?id=26102
+    readonly attribute unsigned long size;
+    void forEach(HeadersForEachCallback callback, optional any thisArg);
 };