zygote: Don't CHECK if browser gone during zygote startup

content/common/sandbox_linux/sandbox_linux.cc

 // Copyright (c) 2012 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 "content/common/sandbox_linux/sandbox_linux.h"
 
 #include <dirent.h>
 #include <fcntl.h>
 #include <stdint.h>
 #include <sys/resource.h>
@@ skipping 92 matching lines @@
 
 LinuxSandbox::LinuxSandbox()
     : proc_fd_(-1),
       seccomp_bpf_started_(false),
       sandbox_status_flags_(kSandboxLinuxInvalid),
       pre_initialized_(false),
       seccomp_bpf_supported_(false),
       seccomp_bpf_with_tsync_supported_(false),
       yama_is_enforcing_(false),
       initialize_sandbox_ran_(false),
+      exiting_before_initialize_sandbox_(false),
       setuid_sandbox_client_(sandbox::SetuidSandboxClient::Create()) {
   if (setuid_sandbox_client_ == NULL) {
     LOG(FATAL) << "Failed to instantiate the setuid sandbox client.";
   }
 #if defined(ANY_OF_AMTLU_SANITIZER)
   sanitizer_args_ = base::WrapUnique(new __sanitizer_sandbox_arguments);
   *sanitizer_args_ = {0};
 #endif
 }
 
 LinuxSandbox::~LinuxSandbox() {
-  if (pre_initialized_) {
+  if (pre_initialized_ && !exiting_before_initialize_sandbox_) {
     CHECK(initialize_sandbox_ran_);
   }
 }
 
 LinuxSandbox* LinuxSandbox::GetInstance() {
   LinuxSandbox* instance = base::Singleton<LinuxSandbox>::get();
   CHECK(instance);
   return instance;
 }
 
@@ skipping 317 matching lines @@
 
 void LinuxSandbox::StopThreadAndEnsureNotCounted(base::Thread* thread) const {
   DCHECK(thread);
   base::ScopedFD proc_fd(OpenProc(proc_fd_));
   PCHECK(proc_fd.is_valid());
   CHECK(
       sandbox::ThreadHelpers::StopThreadAndWatchProcFS(proc_fd.get(), thread));
 }
 
 }  // namespace content