Revert 46384 - Fix race in zygote_host_linux where socket was being read from and written to on different threads.

Made ZygoteHost methods all run on PROCESS_LAUNCHER thread. PostTask in linux from UI thread to PROCESS_LAUNCHER thread for DidProcessCrash. Changed DidProcessCrash to answer via a callback, which occurs asynchronously on linux. Rework cases in nacl_host, browser_render_process_host, and child_process_host where this method was being called to fit the callback model.

BUG=31737
TEST=none

Review URL: http://codereview.chromium.org/1695026

TBR=kkania@chromium.org
Review URL: http://codereview.chromium.org/1933007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@46429 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 23 insertions, 57 deletions

diff --git a/chrome/browser/child_process_launcher.cc b/chrome/browser/child_process_launcher.cc
index ff7a9d2..206d8a7 100644
--- a/chrome/browser/child_process_launcher.cc
+++ b/chrome/browser/child_process_launcher.cc
@@ -182,14 +182,14 @@ class ChildProcessLauncher::Context
         client_thread_id_, FROM_HERE,
         NewRunnableMethod(
             this,
-            &ChildProcessLauncher::Context::NotifyProcessLaunched,
+            &ChildProcessLauncher::Context::Notify,
 #if defined(OS_LINUX)
             use_zygote,
 #endif
             handle));
   }
 
-  void NotifyProcessLaunched(
+  void Notify(
 #if defined(OS_LINUX)
       bool zygote,
 #endif
@@ -206,59 +206,6 @@ class ChildProcessLauncher::Context
     }
   }
 
-  void DetermineDidProcessCrash() {
-    DCHECK(ChromeThread::CurrentlyOn(client_thread_id_));
-    base::ProcessHandle handle = process_.handle();
-#if defined(OS_LINUX)
-    if (zygote_) {
-      ChromeThread::PostTask(
-          ChromeThread::PROCESS_LAUNCHER, FROM_HERE,
-          NewRunnableMethod(this,
-                            &Context::DetermineDidProcessCrashInternal,
-                            handle));
-    } else
-#endif
-    {
-      DetermineDidProcessCrashInternal(handle);
-    }
-  }
-
-  void DetermineDidProcessCrashInternal(base::ProcessHandle handle) {
-    bool did_crash, child_exited;
-#if defined(OS_LINUX)
-    if (zygote_) {
-      did_crash = Singleton<ZygoteHost>()->DidProcessCrash(handle,
-                                                           &child_exited);
-      ChromeThread::PostTask(
-          client_thread_id_, FROM_HERE,
-          NewRunnableMethod(this,
-                            &Context::OnDidProcessCrashDetermined,
-                            child_exited, did_crash));
-    } else
-#endif
-    {
-      did_crash = base::DidProcessCrash(&child_exited, handle);
-      OnDidProcessCrashDetermined(child_exited, did_crash);
-    }
-  }
-
-  void OnDidProcessCrashDetermined(bool child_exited, bool did_crash) {
-    DCHECK(ChromeThread::CurrentlyOn(client_thread_id_));
-
-    // POSIX: If the process crashed, then the kernel closed the socket for it
-    // and so the child has already died by the time we get here. Since
-    // DidProcessCrash called waitpid with WNOHANG, it'll reap the process.
-    // However, if DidProcessCrash didn't reap the child, we'll need to in
-    // Terminate via ProcessWatcher. So we can't close the handle here.
-    if (child_exited)
-      process_.Close();
-
-    if (client_)
-      client_->OnDidProcessCrashDetermined(did_crash);
-    // The client may have deleted us in the callback. Do not add anything
-    // after this point.
-  }
-
   void Terminate() {
     if (!process_.handle())
       return;
@@ -348,8 +295,27 @@ base::ProcessHandle ChildProcessLauncher::GetHandle() {
   return context_->process_.handle();
 }
 
-void ChildProcessLauncher::DetermineDidProcessCrash() {
-  context_->DetermineDidProcessCrash();
+bool ChildProcessLauncher::DidProcessCrash() {
+  bool did_crash, child_exited;
+  base::ProcessHandle handle = context_->process_.handle();
+#if defined(OS_LINUX)
+  if (context_->zygote_) {
+    did_crash = Singleton<ZygoteHost>()->DidProcessCrash(handle, &child_exited);
+  } else
+#endif
+  {
+    did_crash = base::DidProcessCrash(&child_exited, handle);
+  }
+
+  // POSIX: If the process crashed, then the kernel closed the socket for it
+  // and so the child has already died by the time we get here. Since
+  // DidProcessCrash called waitpid with WNOHANG, it'll reap the process.
+  // However, if DidProcessCrash didn't reap the child, we'll need to in
+  // Terminate via ProcessWatcher. So we can't close the handle here.
+  if (child_exited)
+    context_->process_.Close();
+
+  return did_crash;
 }
 
 void ChildProcessLauncher::SetProcessBackgrounded(bool background) {