Add the ability to defer the initialization of the SyzyAsan crash reporter.

syzygy/agent/asan/reporters/crashpad_reporter.cc

 // Copyright 2016 Google Inc. All Rights Reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
@@ skipping 31 matching lines @@
 // doesn't generalize to other clients. Moving forward we will be adding a
 // generic callback mechanism for instrumented clients to inform the RTL of the
 // crash handler to use.
 bool EnsureCrashpadConnected() {
   static bool initialized = false;
   static bool crashpad_present = false;
 
   // Only initialize once.
   if (initialized)
     return crashpad_present;
-  initialized = true;
 
   // Get the name of the crashpad endpoint, failing if none exists.
   std::unique_ptr<base::Environment> env(base::Environment::Create());
   std::string pipe_name;
   if (!env->GetVar(kCrashpadPipeNameVar, &pipe_name))
     return false;
+
+  // Only flip the initialization bit once we've been able to read the
+  // environment variable to make this work if Crashpad wasn't present
+  // during the process initialization but is here later.
+  initialized = true;
   std::wstring pipe_name_w = base::UTF8ToWide(pipe_name);
 
   // Initialize the crashpad client.
   if (!g_crashpad_client.SetHandlerIPCPipe(pipe_name_w))
     return false;
   if (!g_crashpad_client.UseHandler())
     return false;
 
   crashpad_present = true;
   return true;
@@ skipping 108 matching lines @@
   crashpad_info->set_system_crash_reporter_forwarding(
       crashpad::TriState::kDisabled);
   crashpad_info->set_gather_indirectly_referenced_memory(
       crashpad::TriState::kEnabled, 1 * 1024 * 1024);
   crashpad_info->set_simple_annotations(crash_keys_.get());
 }
 
 }  // namespace reporters
 }  // namespace asan
 }  // namespace agent