Always send a reply to nacl launch requests.

Previously there were many return paths where the reply message would not get sent, which would indefinitely hang the renderer. I also found a leak where if the FILE thread is gone when we try to make the IRT available, the object will be leaked (the the reply message would not be sent either). I tried to find all of the failure cases and ensure the reply message is sent.

BUG=
TEST=

Review URL: http://codereview.chromium.org/8994010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@115413 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 14 insertions, 5 deletions

diff --git a/chrome/browser/nacl_host/nacl_process_host.cc b/chrome/browser/nacl_host/nacl_process_host.cc
index eadffc1..db5b3b0 100644
--- a/chrome/browser/nacl_host/nacl_process_host.cc
+++ b/chrome/browser/nacl_host/nacl_process_host.cc
@@ -225,9 +225,11 @@ bool NaClProcessHost::Launch(
   if (!LaunchSelLdr()) {
     return false;
   }
+
   chrome_render_message_filter_ = chrome_render_message_filter;
-  reply_msg_ = reply_msg;
 
+  // On success, we take responsibility for sending the reply.
+  reply_msg_ = reply_msg;
   return true;
 }
 
@@ -384,8 +386,10 @@ void NaClProcessHost::OnProcessLaunched() {
     SendStart(nacl_browser->IrtFile());
   } else {
     // We're waiting for the IRT to be open.
-    nacl_browser->MakeIrtAvailable(base::Bind(&NaClProcessHost::IrtReady,
-                                              weak_factory_.GetWeakPtr()));
+    if (!nacl_browser->MakeIrtAvailable(
+            base::Bind(&NaClProcessHost::IrtReady,
+                       weak_factory_.GetWeakPtr())))
+      delete this;
   }
 }
 
diff --git a/chrome/browser/nacl_host/nacl_process_host.h b/chrome/browser/nacl_host/nacl_process_host.h
index 265e34f..1943c13 100644
--- a/chrome/browser/nacl_host/nacl_process_host.h
+++ b/chrome/browser/nacl_host/nacl_process_host.h
@@ -31,7 +31,10 @@ class NaClProcessHost : public BrowserChildProcessHost {
   // Do any minimal work that must be done at browser startup.
   static void EarlyStartup();
 
-  // Initialize the new NaCl process, returning true on success.
+  // Initialize the new NaCl process, returning true on success. On success,
+  // the NaCl process host will assume responsibility for sending the reply
+  // message. On failure, the reply will not be sent and this is the caller's
+  // responsibility to avoid hanging the renderer.
   bool Launch(ChromeRenderMessageFilter* chrome_render_message_filter,
               int socket_count,
               IPC::Message* reply_msg);
@@ -62,7 +65,9 @@ class NaClProcessHost : public BrowserChildProcessHost {
   // this for sending the reply once the process has started.
   scoped_refptr<ChromeRenderMessageFilter> chrome_render_message_filter_;
 
-  // The reply message to send.
+  // The reply message to send. We must always send this message when the
+  // sub-process either succeeds or fails to unblock the renderer waiting for
+  // the reply. NULL when there is no reply to send.
   IPC::Message* reply_msg_;
 
   // Socket pairs for the NaCl process and renderer.