SandboxIPCProcess: make shutdown mechanism explicit.

content/browser/renderer_host/sandbox_ipc_linux.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 "content/browser/renderer_host/sandbox_ipc_linux.h"
 
 #include <fcntl.h>
 #include <fontconfig/fontconfig.h>
 #include <sys/poll.h>
 #include <sys/socket.h>
@@ skipping 151 matching lines @@
       PLOG(WARNING) << "poll";
       if (failed_polls++ == 3) {
         LOG(FATAL) << "poll(2) failing. RenderSandboxHostLinux aborting.";
         return;
       }
       continue;
     }
 
     failed_polls = 0;
 
+    // The browser process will close the other end of this pipe on shutdown,
+    // so we should exit.
     if (pfds[0].revents) {
-      // our parent died so we should too.
-      _exit(0);
+      break;
     }
 
     if (pfds[1].revents) {
       HandleRequestFromRenderer(browser_socket_);
     }
   }
+
+  VLOG(1) << "SandboxIPCProcess stopping.";
 }
 
 void SandboxIPCProcess::HandleRequestFromRenderer(int fd) {
   ScopedVector<base::ScopedFD> fds;
 
   // A FontConfigIPC::METHOD_MATCH message could be kMaxFontFamilyLength
   // bytes long (this is the largest message type).
   // 128 bytes padding are necessary so recvmsg() does not return MSG_TRUNC
   // error for a maximum length message.
   char buf[FontConfigIPC::kMaxFontFamilyLength + 128];
@@ skipping 426 matching lines @@
 }
 
 void SandboxIPCProcess::EnsureWebKitInitialized() {
   if (webkit_platform_support_)
     return;
   webkit_platform_support_.reset(new BlinkPlatformImpl);
   blink::initializeWithoutV8(webkit_platform_support_.get());
 }
 
 }  // namespace content