[webcrypto] Replace KeyAlgorithm interfaces with an Object.

Source/bindings/core/v8/Dictionary.h

Index: Source/bindings/core/v8/Dictionary.h
diff --git a/Source/bindings/core/v8/Dictionary.h b/Source/bindings/core/v8/Dictionary.h
index 3453b41ed43d65437b0ac7c6eec62433e2a1a0f2..ce4170b2e4d325f2570660cb8831f5bed15083c4 100644
--- a/Source/bindings/core/v8/Dictionary.h
+++ b/Source/bindings/core/v8/Dictionary.h
@@ -66,6 +66,8 @@ class Dictionary {
     ALLOW_ONLY_INLINE_ALLOCATION();
 public:
     Dictionary();
+    // Creates an empty dictionary
+    explicit Dictionary(v8::Isolate*);
     Dictionary(const v8::Handle<v8::Value>& options, v8::Isolate*);
     ~Dictionary();
 
@@ -108,6 +110,14 @@ public:
     bool get(const String&, RefPtr<HeaderMap>&) const;
     bool get(const String&, RefPtr<Headers>&) const;
 
+    // Sets properties using default attributes.
+    bool set(const String&, const v8::Handle<v8::Value>&);
+    bool set(const String&, const String&);
+    bool set(const String&, unsigned);
+    bool set(const String&, const Dictionary&);
+
+    v8::Handle<v8::Value> v8Value() const { return m_options; }
+
     class ConversionContext {
     public:
         ConversionContext(const String& interfaceName, const String& methodName, ExceptionState& exceptionState)