Linux Sandbox: Stop GPU watchdog in accountable way.

content/gpu/gpu_main.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 <stdlib.h>
 
 #if defined(OS_WIN)
 #include <dwmapi.h>
 #include <windows.h>
 #endif
@@ skipping 404 matching lines @@
 
 bool StartSandboxLinux(const gpu::GPUInfo& gpu_info,
                        GpuWatchdogThread* watchdog_thread,
                        bool should_initialize_gl_context) {
   TRACE_EVENT0("gpu", "Initialize sandbox");
 
   bool res = false;
 
   WarmUpSandboxNvidia(gpu_info, should_initialize_gl_context);
 
-  if (watchdog_thread)
-    watchdog_thread->Stop();
+  if (watchdog_thread) {
+    // LinuxSandbox needs to be able to ensure that the thread
+    // has really been stopped.
+    LinuxSandbox::StopThread(watchdog_thread);
+  }
   // LinuxSandbox::InitializeSandbox() must always be called
   // with only one thread.
   res = LinuxSandbox::InitializeSandbox();
-  if (watchdog_thread)
+  if (watchdog_thread) {
     watchdog_thread->Start();
+  }
 
   return res;
 }
 #endif  // defined(OS_LINUX)
 
 #if defined(OS_WIN)
 bool StartSandboxWindows(const sandbox::SandboxInterfaceInfo* sandbox_info) {
   TRACE_EVENT0("gpu", "Lower token");
 
   // For Windows, if the target_services interface is not zero, the process
   // is sandboxed and we must call LowerToken() before rendering untrusted
   // content.
   sandbox::TargetServices* target_services = sandbox_info->target_services;
   if (target_services) {
     target_services->LowerToken();
     return true;
   }
 
   return false;
 }
 #endif  // defined(OS_WIN)
 
 }  // namespace.
 
 }  // namespace content