Use an explicit PID for duplicating Pepper handles rather than the Channel's.

content/browser/plugin_service_impl.cc

Index: content/browser/plugin_service_impl.cc
diff --git a/content/browser/plugin_service_impl.cc b/content/browser/plugin_service_impl.cc
index 6de5daca97051ed494bb5c7afac642c6f9f9f905..40fd937eb7385059ad6a381a9ae60e412907e467 100644
--- a/content/browser/plugin_service_impl.cc
+++ b/content/browser/plugin_service_impl.cc
@@ -342,7 +342,7 @@ void PluginServiceImpl::OpenChannelToPpapiPlugin(
     plugin_host->OpenChannelToPlugin(client);
   } else {
     // Send error.
-    client->OnPpapiChannelOpened(IPC::ChannelHandle(), 0);
+    client->OnPpapiChannelOpened(IPC::ChannelHandle(), base::kNullProcessId, 0);
   }
 }
 
@@ -354,7 +354,7 @@ void PluginServiceImpl::OpenChannelToPpapiBroker(
     plugin_host->OpenChannelToPlugin(client);
   } else {
     // Send error.
-    client->OnPpapiChannelOpened(IPC::ChannelHandle(), 0);
+    client->OnPpapiChannelOpened(IPC::ChannelHandle(), base::kNullProcessId, 0);
   }
 }