Reland r54418 - base: Add UnSetEnv function to EnvVarGetter API.

chrome/browser/zygote_host_linux.cc

 // Copyright (c) 2010 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 "chrome/browser/zygote_host_linux.h"
 
 #include <sys/socket.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
 
 #include "base/command_line.h"
 #include "base/eintr_wrapper.h"
+#include "base/env_var.h"
 #include "base/linux_util.h"
 #include "base/logging.h"
 #include "base/path_service.h"
 #include "base/pickle.h"
 #include "base/process_util.h"
 #include "base/string_number_conversions.h"
 #include "base/string_util.h"
+#include "base/scoped_ptr.h"
 #include "base/unix_domain_socket_posix.h"
 
 #include "chrome/browser/renderer_host/render_sandbox_host_linux.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/process_watcher.h"
 
 #include "sandbox/linux/suid/suid_unsafe_environment_variables.h"
 
 static void SaveSUIDUnsafeEnvironmentVariables() {
   // The ELF loader will clear many environment variables so we save them to
   // different names here so that the SUID sandbox can resolve them for the
   // renderer.
 
   for (unsigned i = 0; kSUIDUnsafeEnvironmentVariables[i]; ++i) {
     const char* const envvar = kSUIDUnsafeEnvironmentVariables[i];
     char* const saved_envvar = SandboxSavedEnvironmentVariable(envvar);
     if (!saved_envvar)
       continue;
 
-    const char* const value = getenv(envvar);
-    if (value)
-      setenv(saved_envvar, value, 1 /* overwrite */);
+    scoped_ptr<base::EnvVarGetter> env(base::EnvVarGetter::Create());
+    std::string value;
+    if (env->GetEnv(envvar, &value))
+      env->SetEnv(saved_envvar, value);
     else
-      unsetenv(saved_envvar);
+      env->UnSetEnv(saved_envvar);
 
     free(saved_envvar);
   }
 }
 
 ZygoteHost::ZygoteHost()
     : pid_(-1),
       init_(false),
       using_suid_sandbox_(false),
       have_read_sandbox_status_word_(false) {
@@ skipping 276 matching lines @@
       !read_pickle.ReadBool(&iter, &tmp_child_exited)) {
     LOG(WARNING) << "Error parsing DidProcessCrash response from zygote.";
     return false;
   }
 
   if (child_exited)
     *child_exited = tmp_child_exited;
 
   return did_crash;
 }