plugins: use OnChannelError to detect when the channel goes away

chrome/browser/utility_process_host_unittest.cc

Index: chrome/browser/utility_process_host_unittest.cc
diff --git a/chrome/browser/utility_process_host_unittest.cc b/chrome/browser/utility_process_host_unittest.cc
index b813cb51f3a83a6a236903ce236f572d0a8c49ee..426f8ba2c0cac58be7973a1e0e28823f9b70d95e 100644
--- a/chrome/browser/utility_process_host_unittest.cc
+++ b/chrome/browser/utility_process_host_unittest.cc
@@ -106,8 +106,10 @@ TEST_F(UtilityProcessHostTest, ExtensionUnpacker) {
   scoped_refptr<TestUtilityProcessHostClient> client(
       new TestUtilityProcessHostClient(&message_loop_));
   ResourceDispatcherHost rdh(NULL);
-  TestUtilityProcessHost process_host(client.get(), &message_loop_, &rdh);
-  process_host.StartExtensionUnpacker(
+  TestUtilityProcessHost* process_host =
+      new TestUtilityProcessHost(client.get(), &message_loop_, &rdh);
+  // process_host will delete itself when it's done.
+  process_host->StartExtensionUnpacker(
       temp_extension_dir.AppendASCII("theme.crx"));
   message_loop_.Run();
   EXPECT_TRUE(client->success());