Update MediaKeySession events to match latest EME spec

Source/platform/drm/ContentDecryptionModuleSession.h

Index: Source/platform/drm/ContentDecryptionModuleSession.h
diff --git a/Source/platform/drm/ContentDecryptionModuleSession.h b/Source/platform/drm/ContentDecryptionModuleSession.h
index ef58745ab67e209642806d420102fb4eb3dd73e7..ee1154f6bcf026cacd308c56a9289c9f5ba67ab4 100644
--- a/Source/platform/drm/ContentDecryptionModuleSession.h
+++ b/Source/platform/drm/ContentDecryptionModuleSession.h
@@ -52,9 +52,10 @@ class KURL;
 class PLATFORM_EXPORT ContentDecryptionModuleSessionClient {
 public:
     enum MediaKeyErrorCode { UnknownError = 1, ClientError };
-    virtual void keyAdded() = 0;
     virtual void keyError(MediaKeyErrorCode, unsigned long systemCode) = 0;

[xhwang, 2014/01/03 23:38:20]

Here and everywhere, we should drop the "Key" part. OnError() or
OnSessionError()?

[ddorwin, 2014/01/07 23:44:41]

+1
"Session" is redundant. Is "On" common in Blink?
Looking at WebMediaPlayerClient.h, it seems not, but I don't know if that's a
good example.

[jrummell, 2014/01/08 18:05:52]

Done. I couldn't find any examples of Onxxx anywhere in Blink.

     virtual void keyMessage(const unsigned char* message, size_t messageLength, const KURL& destinationURL) = 0;
+    virtual void keyReady() = 0;

[ddorwin, 2014/01/07 23:44:41]

These had been in alphabetical order. The Chromium code now uses "lifecycle"
order. The EME spec had been alphabetical before "closed" was added, but I think
I'll reorder it to "lifecycle", which MSE appears to use.

In summary, I think we should use "lifecycle" order. WDYT? This probably applies
to other files in this CL too.

[jrummell, 2014/01/08 18:05:52]

Prefer lifecycle order, so moved Error() to end of list.

+    virtual void keyClosed() = 0;
 };
 
 class PLATFORM_EXPORT ContentDecryptionModuleSession : private blink::WebContentDecryptionModuleSession::Client {
@@ -72,9 +73,10 @@ public:
 
 private:
     // blink::WebContentDecryptionModuleSession::Client
-    virtual void keyAdded() OVERRIDE;
     virtual void keyError(MediaKeyErrorCode, unsigned long systemCode) OVERRIDE;
     virtual void keyMessage(const unsigned char* message, size_t messageLength, const blink::WebURL& destinationURL) OVERRIDE;
+    virtual void keyReady() OVERRIDE;
+    virtual void keyClosed() OVERRIDE;
 
     OwnPtr<blink::WebContentDecryptionModuleSession> m_session;