Add PpapiDecryptor which wraps a CDM plugin.

webkit/media/crypto/proxy_decryptor.cc

Index: webkit/media/crypto/proxy_decryptor.cc
diff --git a/webkit/media/crypto/proxy_decryptor.cc b/webkit/media/crypto/proxy_decryptor.cc
index 0c9646452325c69a2a93bbebbf586e4377f2ed70..3f89fedb4059c12be8f0bfcd07d4113cc9f92e37 100644
--- a/webkit/media/crypto/proxy_decryptor.cc
+++ b/webkit/media/crypto/proxy_decryptor.cc
@@ -12,8 +12,10 @@
 
 namespace webkit_media {
 
-ProxyDecryptor::ProxyDecryptor(media::DecryptorClient* client)
-    : client_(client) {
+ProxyDecryptor::ProxyDecryptor(media::DecryptorClient* client,
+                               const CreatePluginCB& create_plugin_cb)
+    : client_(client),
+      create_plugin_cb_(create_plugin_cb) {
 }
 
 ProxyDecryptor::~ProxyDecryptor() {
@@ -26,7 +28,7 @@ void ProxyDecryptor::GenerateKeyRequest(const std::string& key_system,
   // only creates a new decryptor when |decryptor_| is not initialized.
   if (!decryptor_.get()) {
     base::AutoLock auto_lock(lock_);
-    decryptor_ = CreateDecryptor(key_system, client_);
+    decryptor_ = CreateDecryptor(key_system, client_, create_plugin_cb_);

[ddorwin, 2012/07/17 21:31:28]

As mentioned in ppapi_decryptor.cc, I think we should separate initialization
from GKR.
One additional advantage is we can avoid storing this CB.
If we do it in a Create() or Init() method, we could pass in frame_, etc. to
that method and not need a create_plugin_cb, which is specific to one type of
Decryptor.

From there, we can try to solve this call. Maybe it creates the appropriate
object, and we call Init() with client and frame_and it does the right thing.

We have to pass some extra types around, but at least the pattern is the same
for all types and PluginInstance is not exposed. The only other option seems to
be moving creation to this class, which would separate the key string code or
require exposing "GetDecryptorTypeForKeySystem()".

[xhwang, 2012/07/18 19:43:17]

Done.

   }
 
   DCHECK(decryptor_.get());