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

content/common/sandbox_linux/sandbox_linux.h

Index: content/common/sandbox_linux/sandbox_linux.h
diff --git a/content/common/sandbox_linux/sandbox_linux.h b/content/common/sandbox_linux/sandbox_linux.h
index 6b15562119094fa40c308f2f066a8d9b5402beab..407534180fb9084055ea232d7bc8d05b47c267b6 100644
--- a/content/common/sandbox_linux/sandbox_linux.h
+++ b/content/common/sandbox_linux/sandbox_linux.h
@@ -139,6 +139,10 @@ class LinuxSandbox {
   };
 #endif
 
+  void set_exiting_before_initialize_sandbox(bool exiting) {
+    exiting_before_initialize_sandbox_ = exiting;
+  }
+
  private:
   friend struct base::DefaultSingletonTraits<LinuxSandbox>;
 
@@ -179,6 +183,9 @@ class LinuxSandbox {
   bool seccomp_bpf_with_tsync_supported_;  // Accurate if pre_initialized_.
   bool yama_is_enforcing_;  // Accurate if pre_initialized_.
   bool initialize_sandbox_ran_;  // InitializeSandbox() was called.
+  // Set when exiting due to error during startup. Allows shutdown to happen
+  // without verifying that InitializeSandbox() was called.
+  bool exiting_before_initialize_sandbox_;
   std::unique_ptr<sandbox::SetuidSandboxClient> setuid_sandbox_client_;
 #if defined(ANY_OF_AMTLU_SANITIZER)
   std::unique_ptr<__sanitizer_sandbox_arguments> sanitizer_args_;