Implement MediaKeySession close() and remove()

public/platform/WebContentDecryptionModuleSession.h

Index: public/platform/WebContentDecryptionModuleSession.h
diff --git a/public/platform/WebContentDecryptionModuleSession.h b/public/platform/WebContentDecryptionModuleSession.h
index ab08884ff61732ada3719cee68ebb52a8e538f83..49820de3623c70e18483aacb90f2c5da1109c73a 100644
--- a/public/platform/WebContentDecryptionModuleSession.h
+++ b/public/platform/WebContentDecryptionModuleSession.h
@@ -65,14 +65,10 @@ public:
     virtual void setClientInterface(Client*) = 0;
     virtual WebString sessionId() const = 0;
 
-    // FIXME: Remove these methods once the new methods are implemented in Chromium.
-    virtual void initializeNewSession(const WebString& mimeType, const unsigned char* initData, size_t initDataLength) = 0;
-    virtual void update(const unsigned char* response, size_t responseLength) = 0;
-    virtual void release() = 0;
-
-    virtual void initializeNewSession(const WebString& initDataType, const unsigned char* initData, size_t initDataLength, const WebString& sessionType, WebContentDecryptionModuleResult);
-    virtual void update(const unsigned char* response, size_t responseLength, WebContentDecryptionModuleResult);
-    virtual void release(WebContentDecryptionModuleResult);
+    virtual void initializeNewSession(const WebString& initDataType, const unsigned char* initData, size_t initDataLength, const WebString& sessionType, WebContentDecryptionModuleResult) = 0;
+    virtual void update(const unsigned char* response, size_t responseLength, WebContentDecryptionModuleResult) = 0;
+    virtual void close(WebContentDecryptionModuleResult) = 0;
+    virtual void remove(WebContentDecryptionModuleResult) = 0;
 };
 
 } // namespace blink