Encrypted Media: Allows empty key message to be fired.

ppapi/proxy/ppb_instance_proxy.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ppapi/proxy/ppb_instance_proxy.h"
 
 #include "base/memory/ref_counted.h"
 #include "build/build_config.h"
 #include "ppapi/c/pp_errors.h"
 #include "ppapi/c/pp_time.h"
@@ skipping 521 matching lines @@
           instance,
           SerializedVarSendInput(dispatcher(), key_system),
           SerializedVarSendInput(dispatcher(), session_id)));
 }
 
 void PPB_Instance_Proxy::KeyMessage(PP_Instance instance,
                                     PP_Var key_system,
                                     PP_Var session_id,
                                     PP_Resource message,
                                     PP_Var default_url) {
-  Resource* object =
-      PpapiGlobals::Get()->GetResourceTracker()->GetResource(message);
-  if (!object || object->pp_instance() != instance)
-    return;
+  PP_Resource host_resource = 0;
+  if (message) {
+    Resource* object =
+        PpapiGlobals::Get()->GetResourceTracker()->GetResource(message);
+    if (!object || object->pp_instance() != instance)
+      return;
+    host_resource = object->host_resource().host_resource();
+  }
+
   dispatcher()->Send(
       new PpapiHostMsg_PPBInstance_KeyMessage(
           API_ID_PPB_INSTANCE,
           instance,
           SerializedVarSendInput(dispatcher(), key_system),
           SerializedVarSendInput(dispatcher(), session_id),
-          object->host_resource().host_resource(),
+          host_resource,
           SerializedVarSendInput(dispatcher(), default_url)));
 }
 
 void PPB_Instance_Proxy::KeyError(PP_Instance instance,
                                   PP_Var key_system,
                                   PP_Var session_id,
                                   int32_t media_error,
                                   int32_t system_code) {
   dispatcher()->Send(
       new PpapiHostMsg_PPBInstance_KeyError(
@@ skipping 643 matching lines @@
     PP_Instance instance) {
   InstanceData* data = static_cast<PluginDispatcher*>(dispatcher())->
       GetInstanceData(instance);
   if (!data)
     return;  // Instance was probably deleted.
   data->should_do_request_surrounding_text = false;
 }
 
 }  // namespace proxy
 }  // namespace ppapi