Support LoadSession() in MediaKeys and PPP_ContentDecryptor_Private interface.

content/renderer/media/crypto/proxy_decryptor.cc

Index: content/renderer/media/crypto/proxy_decryptor.cc
diff --git a/content/renderer/media/crypto/proxy_decryptor.cc b/content/renderer/media/crypto/proxy_decryptor.cc
index 2e1b81a3df39e32ecea75909c9b411035f1feba6..4dd64aae7e6faa455e81df283ab88b893f89a77c 100644
--- a/content/renderer/media/crypto/proxy_decryptor.cc
+++ b/content/renderer/media/crypto/proxy_decryptor.cc
@@ -83,17 +83,32 @@ bool ProxyDecryptor::InitializeCDM(const std::string& key_system,
   return true;
 }
 
-bool ProxyDecryptor::GenerateKeyRequest(const std::string& type,
+bool ProxyDecryptor::GenerateKeyRequest(const std::string& content_type,
                                         const uint8* init_data,
                                         int init_data_length) {
   // Use a unique reference id for this request.
   uint32 session_id = next_session_id_++;
-  if (!media_keys_->CreateSession(
-           session_id, type, init_data, init_data_length)) {
-    return false;
+
+  const uint8 kPrefixedApiLoadSessionHeader[] = "LOAD_SESSION|";
+  const int kPrefixedApiLoadSessionHeaderLength =
+      sizeof(kPrefixedApiLoadSessionHeader) - 1;
+
+  if (init_data_length > kPrefixedApiLoadSessionHeaderLength &&
+      std::equal(init_data,
+                 init_data + kPrefixedApiLoadSessionHeaderLength,
+                 kPrefixedApiLoadSessionHeader)) {
+    // TODO(xhwang): Track loadable session to handle OnSessionClosed().
+    // See: http://crbug.com/340859.
+    media_keys_->LoadSession(
+        session_id,
+        std::string(reinterpret_cast<const char*>(
+                        init_data + kPrefixedApiLoadSessionHeaderLength),
+                    init_data_length - kPrefixedApiLoadSessionHeaderLength));
+    return true;
   }
 
-  return true;
+  return media_keys_->CreateSession(
+      session_id, content_type, init_data, init_data_length);
 }
 
 void ProxyDecryptor::AddKey(const uint8* key,