Adds debugging info to track down service launch race

services/shell/service_manager.cc

 // Copyright 2014 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 "services/shell/service_manager.h"
 
 #include <stdint.h>
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/command_line.h"
+#include "base/debug/alias.h"
 #include "base/guid.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/process/process.h"
 #include "base/process/process_handle.h"
 #include "base/stl_util.h"
 #include "base/strings/string_util.h"
 #include "base/trace_event/trace_event.h"
 #include "mojo/public/cpp/bindings/binding.h"
 #include "mojo/public/cpp/bindings/binding_set.h"
@@ skipping 791 matching lines @@
     // Otherwise we create a new Service pipe.
     mojom::ServiceRequest request = GetProxy(&service);
     CHECK(!result->package_path.empty() && result->capabilities.has_value());
 
     if (target.name() != result->resolved_name) {
       instance->StartWithService(std::move(service));
       Identity factory(result->resolved_name, target.user_id(),
                        instance_name);
       CreateServiceWithFactory(factory, target.name(), std::move(request));
     } else {
+      Identity source_instance_identity;
+      base::debug::Alias(&has_source_instance);
+      base::FilePath package_path = result->package_path;
+      base::debug::Alias(&package_path);
+      base::debug::Alias(&source);
+      base::debug::Alias(&target);
+      if (source_instance)
+        source_instance_identity = source_instance->identity();
+      base::debug::Alias(&source_instance_identity);
+#if defined(GOOGLE_CHROME_BUILD)
+      // We do not currently want to hit this code path in production, but it's
+      // happening somehow. https://crbug.com/649673.
+      CHECK(false);

[xhwang, 2016/12/03 00:25:31]

I am hitting this CHECK when running a ServiceTest with is_chrome_branded=true.
I feel the test is valid even with is_chrome_branded=true. Ideas?

+#endif
       instance->StartWithFilePath(result->package_path);
     }
   }
 
   // Now that the instance has a Service, we can connect to it.
   bool connected = instance->ConnectToService(&params);
   DCHECK(connected);
 }
 
 base::WeakPtr<ServiceManager> ServiceManager::GetWeakPtr() {
   return weak_ptr_factory_.GetWeakPtr();
 }
 
 }  // namespace shell