Make M-x shell work in emacs.

build_tools/naclprocess.js

Index: build_tools/naclprocess.js
diff --git a/build_tools/naclprocess.js b/build_tools/naclprocess.js
index f522fff2cf5dd0ece2a85e1498b7ad9a7889b730..f8ce45f63146dffd0da162ae6e1161a4b8facefb 100644
--- a/build_tools/naclprocess.js
+++ b/build_tools/naclprocess.js
@@ -1156,7 +1156,6 @@ NaClProcessManager.prototype.spawn = function (
     }
 
     var fg = document.createElement('object');
-    self.foregroundProcess = fg;
 
     var ppid;
     if (pid === -1) {
@@ -1303,7 +1302,14 @@ NaClProcessManager.prototype.spawn = function (
       });
     }
 
-    self.pipeServer.addProcessPipes(fg.pid, params);
+    // Add in process pipes, and only make the foreground process if started
+    // by the current foreground process and not piped somewhere else.
+    var routesStdin = self.pipeServer.addProcessPipes(fg.pid, params);
+    if (!routesStdin &&
+        (self.foregroundProcess === null ||
+         self.foregroundProcess === parent)) {
+      self.foregroundProcess = fg;
+    }
 
     if (params[NaClProcessManager.ENV_SPAWN_MODE] ===
         NaClProcessManager.ENV_SPAWN_POPUP_VALUE) {