Introduce CdmContext interface.

media/cdm/proxy_decryptor.cc

Index: media/cdm/proxy_decryptor.cc
diff --git a/media/cdm/proxy_decryptor.cc b/media/cdm/proxy_decryptor.cc
index 92856ff32bf46c4f6b1c8bbf20aa9081e5ffd318..0c25dff741643549732234164838482b615869f0 100644
--- a/media/cdm/proxy_decryptor.cc
+++ b/media/cdm/proxy_decryptor.cc
@@ -43,12 +43,12 @@ ProxyDecryptor::~ProxyDecryptor() {
 }
 
 Decryptor* ProxyDecryptor::GetDecryptor() {

[ddorwin, 2014/11/21 05:04:27]

It doesn't matter much, but we _could_ possibly return a CdmContext instead.
Does that make the prefixed and unprefixed paths more similar?

[xhwang, 2014/11/21 05:15:41]

This will return a CdmContext in the next CL.

-  return media_keys_ ? media_keys_->GetDecryptor() : NULL;
+  return media_keys_ ? media_keys_->GetCdmContext()->GetDecryptor() : NULL;
 }
 
 #if defined(ENABLE_BROWSER_CDMS)
 int ProxyDecryptor::GetCdmId() {
-  return media_keys_->GetCdmId();
+  return media_keys_->GetCdmContext()->GetCdmId();
 }
 #endif