Add new needkey event for EME.

public/platform/WebMediaPlayerClient.h

Index: public/platform/WebMediaPlayerClient.h
diff --git a/public/platform/WebMediaPlayerClient.h b/public/platform/WebMediaPlayerClient.h
index d86108ca0fd925a12f51ad944cba488751bfac6b..290bf5242aeda182e224573c4443d7d081f3671e 100644
--- a/public/platform/WebMediaPlayerClient.h
+++ b/public/platform/WebMediaPlayerClient.h
@@ -68,6 +68,7 @@ public:
     virtual void keyError(const WebString& keySystem, const WebString& sessionId, MediaKeyErrorCode, unsigned short systemCode) = 0;
     virtual void keyMessage(const WebString& keySystem, const WebString& sessionId, const unsigned char* message, unsigned messageLength, const WebURL& defaultURL) = 0;
     virtual void keyNeeded(const WebString& keySystem, const WebString& sessionId, const unsigned char* initData, unsigned initDataLength) = 0;
+    virtual void keyNeeded(const WebString& contentType, const unsigned char* initData, unsigned initDataLength) = 0;
     // The returned pointer is valid until closeHelperPlugin() is called.
     // Returns 0 if the plugin could not be instantiated.
     virtual WebPlugin* createHelperPlugin(const WebString& pluginType, WebFrame*) = 0;