Launch processes asynchronously so as not to block the UI thread. For now, renderer only, I'll take care of plugin/worker/utility processes in a followup change.

BUG=6844
Review URL: http://codereview.chromium.org/397002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@32203 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 61 insertions, 0 deletions

diff --git a/chrome/browser/child_process_launcher.h b/chrome/browser/child_process_launcher.h
new file mode 100644
index 0000000..a2c02f3
--- /dev/null
+++ b/chrome/browser/child_process_launcher.h
@@ -0,0 +1,61 @@
+// Copyright (c) 2009 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.
+
+#ifndef CHROME_COMMON_CHILD_PROCESS_LAUNCHER_H_
+#define CHROME_COMMON_CHILD_PROCESS_LAUNCHER_H_
+
+#include "base/basictypes.h"
+#include "base/process.h"
+#include "base/ref_counted.h"
+
+class CommandLine;
+
+namespace IPC {
+class SyncChannel;
+}
+
+// Launches a process asynchronously and notifies the client of the process
+// handle when it's available.  It's used to avoid blocking the calling thread
+// on the OS since often it can take > 100 ms to create the process.
+class ChildProcessLauncher {
+ public:
+  class Client {
+   public:
+    // Will be called on the thread that the ChildProcessLauncher was
+    // constructed on.
+    virtual void OnProcessLaunched() = 0;
+  };
+
+  // Launches the process asynchronously, calling the client when the result is
+  // ready.  Deleting this object before the process is created is safe, since
+  // the callback won't be called.  If the process is still running by the time
+  // this object destructs, it will be terminated.
+  // Takes ownership of cmd_line.
+  ChildProcessLauncher(CommandLine* cmd_line,
+                       IPC::SyncChannel* channel,
+                       Client* client);
+  ~ChildProcessLauncher();
+
+  // True if the process is being launched and so the handle isn't available.
+  bool IsStarting();
+
+  // Getter for the process handle.  Only call after the process has started.
+  base::ProcessHandle GetHandle();
+
+  // Call this when the process exits to know if a process crashed or not.
+  bool DidProcessCrash();
+
+  // Changes whether the process runs in the background or not.  Only call
+  // this after the process has started.
+  void SetProcessBackgrounded(bool background);
+
+ private:
+  class Context;
+
+  scoped_refptr<Context> context_;
+
+  DISALLOW_COPY_AND_ASSIGN(ChildProcessLauncher);
+};
+
+#endif  // CHROME_COMMON_CHILD_PROCESS_LAUNCHER_H_