[chromedriver] Add chrome.detach option for configuring Chrome not to quit

chrome/test/webdriver/webdriver_automation.cc

Index: chrome/test/webdriver/webdriver_automation.cc
diff --git a/chrome/test/webdriver/webdriver_automation.cc b/chrome/test/webdriver/webdriver_automation.cc
index f410842a73159193efb8d3d761ff422b6fc92e0a..9d218372a6866442e09f49c86c03154178602e21 100644
--- a/chrome/test/webdriver/webdriver_automation.cc
+++ b/chrome/test/webdriver/webdriver_automation.cc
@@ -184,7 +184,8 @@ bool GetDefaultChromeExe(FilePath* browser_exe) {
 namespace webdriver {
 
 Automation::BrowserOptions::BrowserOptions()
-    : command(CommandLine::NO_PROGRAM) {}
+    : command(CommandLine::NO_PROGRAM),
+      detach_process(false) {}
 
 Automation::BrowserOptions::~BrowserOptions() {}
 
@@ -201,6 +202,8 @@ void Automation::Init(const BrowserOptions& options, Error** error) {
   command.AppendSwitch(switches::kFullMemoryCrashReport);
   command.AppendSwitch(switches::kNoDefaultBrowserCheck);
   command.AppendSwitch(switches::kNoFirstRun);
+  if (options.detach_process)
+    command.AppendSwitch(switches::kAutomationReinitializeOnChannelError);
   if (options.user_data_dir.empty())
     command.AppendSwitchASCII(switches::kHomePage, chrome::kAboutBlankURL);
 
@@ -228,10 +231,35 @@ void Automation::Init(const BrowserOptions& options, Error** error) {
   LOG(INFO) << chrome_details;
 
   // Create the ProxyLauncher and launch Chrome.
-  if (options.channel_id.empty()) {
+  // In Chrome 13/14, the only way to detach the browser process is to use a
+  // named proxy launcher.
+  // TODO(kkania): Remove this when Chrome 15 is stable.
+  std::string channel_id = options.channel_id;
+  bool launch_browser = false;
+  if (options.detach_process) {
+    launch_browser = true;
+    if (!channel_id.empty()) {
+      *error = new Error(
+          kUnknownError, "Cannot detach an already running browser process");
+      return;
+    }
+#if defined(OS_WIN)
+    channel_id = "chromedriver" + GenerateRandomID();
+#elif defined(OS_POSIX)
+    FilePath temp_file;
+    if (!file_util::CreateTemporaryFile(&temp_file) ||
+        !file_util::Delete(temp_file, false /* recursive */)) {
+      *error = new Error(kUnknownError, "Could not create temporary filename");
+      return;
+    }
+    channel_id = temp_file.value();
+#endif
+  }
+  if (channel_id.empty()) {
     launcher_.reset(new AnonymousProxyLauncher(false));
   } else {
-    launcher_.reset(new NamedProxyLauncher(options.channel_id, false, false));
+    LOG(INFO) << "Using named testing interface";
+    launcher_.reset(new NamedProxyLauncher(channel_id, launch_browser, false));
   }
   ProxyLauncher::LaunchState launch_props = {
       false,  // clear_profile