Merge 249937 "Linux Sandbox: Stop GPU watchdog in accountable way."

content/gpu/gpu_main.cc

Index: content/gpu/gpu_main.cc
===================================================================
--- content/gpu/gpu_main.cc	(revision 251104)
+++ content/gpu/gpu_main.cc	(working copy)
@@ -403,13 +403,17 @@
 
   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;
 }