Browser watcher, part deux.

components/browser_watcher/watcher_client_win.h

Index: components/browser_watcher/watcher_client_win.h
diff --git a/components/browser_watcher/watcher_client_win.h b/components/browser_watcher/watcher_client_win.h
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+// Copyright (c) 2014 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 COMPONENTS_BROWSER_WATCHER_WATCHER_CLIENT_WIN_H_
+#define COMPONENTS_BROWSER_WATCHER_WATCHER_CLIENT_WIN_H_
+
+#include "base/command_line.h"
+#include "base/macros.h"
+#include "base/process/process_handle.h"
+#include "base/win/scoped_handle.h"
+
+namespace browser_watcher {
+
+// An interface class to take care of the details in launching a browser
+// watch process.
+class WatcherClient {
+ public:
+  // Constructs a watcher client with a |base_command_line|, which should be
+  // a command line sufficient to invoke the watcher process. This command
+  // line will be augmented with the value of the inherited handle.
+  explicit WatcherClient(const base::CommandLine& base_command_line);
+
+  // Launches the watcher process.
+  void LaunchWatcher();
+
+  // Accessors, exposed only for testing.
+  bool use_legacy_launch() const { return use_legacy_launch_; }
+  void set_use_legacy_launch(bool use_legacy_launch) {
+      use_legacy_launch_ = use_legacy_launch;
+  }
+  base::ProcessHandle process() const { return process_.Get(); }
+
+ private:
+  // Launches |cmd_line| such that the child process is able to inherit
+  // |handle|. If |use_legacy_launch_| is true, this uses a non-threadsafe
+  // legacy launch mode that's compatible with Windows XP.
+  // Returns a handle to the child process.
+  base::win::ScopedHandle LaunchWatcherProcess(
+        const base::CommandLine& cmd_line, base::ProcessHandle self_handle);
+
+  // If true, the watcher process will be launched with XP legacy handle
+  // inheritance. This is not thread safe and can leak random handles into the
+  // child process, but it's the best we can do on XP.
+  bool use_legacy_launch_;
+
+  // The base command line passed to the constructor.
+  base::CommandLine base_command_line_;
+
+  // A handle to the launched watcher process. Valid after a successful
+  // LaunchWatcher() call.
+  base::win::ScopedHandle process_;
+
+  DISALLOW_COPY_AND_ASSIGN(WatcherClient);
+};
+
+}  // namespace browser_watcher
+
+#endif  // COMPONENTS_BROWSER_WATCHER_WATCHER_CLIENT_WIN_H_