Initialize the CDM asynchronously

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 c30cb837f8be46732740419152cbc15a7e33cd4a..b8ba19c5ebc05994e93e20f2056ed7d9e93ed1e7 100644
--- a/media/cdm/proxy_decryptor.cc
+++ b/media/cdm/proxy_decryptor.cc
@@ -94,15 +94,14 @@ void ProxyDecryptor::OnCdmCreated(const std::string& key_system,
 
   if (!cdm) {
     cdm_context_ready_cb.Run(nullptr);
-    return;
-  }
+  } else {
+    key_system_ = key_system;
+    security_origin_ = security_origin;
+    is_clear_key_ = IsClearKey(key_system) || IsExternalClearKey(key_system);
+    media_keys_ = cdm.Pass();
 
-  key_system_ = key_system;
-  security_origin_ = security_origin;
-  is_clear_key_ = IsClearKey(key_system) || IsExternalClearKey(key_system);
-  media_keys_ = cdm.Pass();
-
-  cdm_context_ready_cb.Run(media_keys_->GetCdmContext());
+    cdm_context_ready_cb.Run(media_keys_->GetCdmContext());
+  }
 
   for (const auto& request : pending_requests_)
     GenerateKeyRequestInternal(request->init_data_type, request->init_data);