Ignore kill termination status when shutting down a child process.

content/common/child_process_host_impl.h

Index: content/common/child_process_host_impl.h
diff --git a/content/common/child_process_host_impl.h b/content/common/child_process_host_impl.h
index 686a7737319084a00491a8e3161508443ad6a6ff..55e768a2a9f13212f52c218f665d8e933dc09d6f 100644
--- a/content/common/child_process_host_impl.h
+++ b/content/common/child_process_host_impl.h
@@ -78,6 +78,7 @@ class CONTENT_EXPORT ChildProcessHostImpl : public ChildProcessHost,
   // ChildProcessHost implementation
   bool Send(IPC::Message* message) override;
   void ForceShutdown() override;
+  bool IsShuttingDown() override;
   std::string CreateChannel() override;
   std::string CreateChannelMojo(const std::string& child_token) override;
   bool IsChannelOpening() override;
@@ -119,6 +120,7 @@ class CONTENT_EXPORT ChildProcessHostImpl : public ChildProcessHost,
   bool opening_channel_;  // True while we're waiting the channel to be opened.
   std::unique_ptr<IPC::Channel> channel_;
   std::string channel_id_;
+  bool is_shutting_down_;
 
   // Holds all the IPC message filters.  Since this object lives on the IO
   // thread, we don't have a IPC::ChannelProxy and so we manage filters