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

chrome/test/webdriver/webdriver_session.cc

 // Copyright (c) 2011 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.
 
 #include "chrome/test/webdriver/webdriver_session.h"
 
 #include <sstream>
 #include <vector>
 
 #include "base/command_line.h"
@@ skipping 75 matching lines @@
       this,
       &Session::InitOnSessionThread,
       options,
       &error));
   if (error)
     Terminate();
   return error;
 }
 
 Error* Session::BeforeExecuteCommand() {
+  Error* error = AfterExecuteCommand();
+  if (!error) {
+    error = SwitchToTopFrameIfCurrentFrameInvalid();
+  }
+  return error;
+}
+
+Error* Session::AfterExecuteCommand() {
   Error* error = NULL;
   if (!options_.load_async) {
     LOG(INFO) << "Waiting for the page to stop loading";
     error = WaitForAllTabsToStopLoading();
     LOG(INFO) << "Done waiting for the page to stop loading";
   }
-  if (!error) {
-    error = SwitchToTopFrameIfCurrentFrameInvalid();
-  }
   return error;
 }
 
 void Session::Terminate() {
   RunSessionTask(NewRunnableMethod(
       this,
       &Session::TerminateOnSessionThread));
   delete this;
 }
 
@@ skipping 1271 matching lines @@
 Error* Session::GetAppCacheStatus(int* status) {
   return ExecuteScriptAndParse(
       current_target_,
       atoms::GET_APPCACHE_STATUS,
       "getAppcacheStatus",
       new ListValue(),
       CreateDirectValueParser(status));
 }
 
 }  // namespace webdriver