Allow null buffer resources to be returned through the PPB_ContentDecryptor_Private proxy.

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 "build/build_config.h"
 #include "ppapi/c/pp_errors.h"
 #include "ppapi/c/pp_time.h"
 #include "ppapi/c/pp_var.h"
@@ skipping 504 matching lines @@
           instance,
           SerializedVarSendInput(dispatcher(), key_system),
           SerializedVarSendInput(dispatcher(), session_id),
           media_error,
           system_code));
 }
 
 void PPB_Instance_Proxy::DeliverBlock(PP_Instance instance,
                                       PP_Resource decrypted_block,
                                       const PP_DecryptedBlockInfo* block_info) {
-  Resource* object =
-      PpapiGlobals::Get()->GetResourceTracker()->GetResource(decrypted_block);
-  if (!object || object->pp_instance() != instance)
-    return;
+  PP_Resource decrypted_block_host_resource = 0;
+
+  if (decrypted_block) {
+    Resource* object =
+        PpapiGlobals::Get()->GetResourceTracker()->GetResource(decrypted_block);
+    if (!object || object->pp_instance() != instance)
+      return;
+    decrypted_block_host_resource = object->host_resource().host_resource();
+  }
 
   std::string serialized_block_info;
   if (!SerializeBlockInfo(*block_info, &serialized_block_info))
     return;
 
   dispatcher()->Send(
       new PpapiHostMsg_PPBInstance_DeliverBlock(API_ID_PPB_INSTANCE,
           instance,
-          object->host_resource().host_resource(),
+          decrypted_block_host_resource,
           serialized_block_info));
 }
 
 void PPB_Instance_Proxy::DecoderInitialized(PP_Instance instance,
                                             PP_Bool success,
                                             uint32_t request_id) {
   dispatcher()->Send(
       new PpapiHostMsg_PPBInstance_DecoderInitialized(
           API_ID_PPB_INSTANCE,
           instance,
@@ skipping 17 matching lines @@
                                           PP_DecryptorStreamType decoder_type,
                                           uint32_t request_id) {
   dispatcher()->Send(
       new PpapiHostMsg_PPBInstance_DecoderResetDone(
           API_ID_PPB_INSTANCE,
           instance,
           decoder_type,
           request_id));
 }
 
+// TODO(tomfinegan): Handle null decrypted_frame after landing other patches.
 void PPB_Instance_Proxy::DeliverFrame(PP_Instance instance,
                                       PP_Resource decrypted_frame,
                                       const PP_DecryptedFrameInfo* frame_info) {
   Resource* object =
       PpapiGlobals::Get()->GetResourceTracker()->GetResource(decrypted_frame);
   if (!object || object->pp_instance() != instance)
     return;
 
   std::string serialized_block_info;
   if (!SerializeBlockInfo(*frame_info, &serialized_block_info))
     return;
 
   dispatcher()->Send(new PpapiHostMsg_PPBInstance_DeliverFrame(
           API_ID_PPB_INSTANCE,
           instance,
           object->host_resource().host_resource(),
           serialized_block_info));
 }
 
+// TODO(tomfinegan): Handle null decrypted_samples after landing other patches.
 void PPB_Instance_Proxy::DeliverSamples(
     PP_Instance instance,
     PP_Resource decrypted_samples,
     const PP_DecryptedBlockInfo* block_info) {
   Resource* object =
       PpapiGlobals::Get()->GetResourceTracker()->GetResource(decrypted_samples);
   if (!object || object->pp_instance() != instance)
     return;
 
   std::string serialized_block_info;
@@ skipping 516 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