Add comment explaining fix and added explicit HistoryService dependency in predictor.

chrome/browser/printing/cloud_print/test/cloud_print_policy_browsertest.cc

 // Copyright (c) 2012 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 "base/command_line.h"
 #include "base/file_util.h"
 #include "base/path_service.h"
 #include "base/process_util.h"
 #include "base/test/test_timeouts.h"
 #include "chrome/common/chrome_notification_types.h"
@@ skipping 40 matching lines @@
                                        TestTimeouts::action_timeout());
 
   EXPECT_TRUE(exited);
   EXPECT_EQ(chrome::RESULT_CODE_NORMAL_EXIT_PROCESS_NOTIFIED, exit_code);
   base::CloseProcessHandle(handle);
 }
 
 IN_PROC_BROWSER_TEST_F(CloudPrintPolicyTest, CloudPrintPolicyFlag) {
   CommandLine new_command_line(GetCommandLineForRelaunch());
   new_command_line.AppendSwitch(switches::kCheckCloudPrintConnectorPolicy);
+  // This is important for the test as the way the browser process is launched
+  // here causes the predictor databases to be initialized multiple times. This
+  // is not an issue for production where the process is launched as a service
+  // and a Profile is not created. See http://crbug.com/140466 for more details.
   new_command_line.AppendSwitchASCII(
       switches::kSpeculativeResourcePrefetching,
       switches::kSpeculativeResourcePrefetchingDisabled);
 
   base::ProcessHandle handle;
   bool launched =
       base::LaunchProcess(new_command_line, base::LaunchOptions(), &handle);
   EXPECT_TRUE(launched);
 
   int exit_code = -100;
   bool exited =
       base::WaitForExitCodeWithTimeout(handle, &exit_code,
                                        TestTimeouts::action_timeout());
 
   EXPECT_TRUE(exited);
   EXPECT_EQ(content::RESULT_CODE_NORMAL_EXIT, exit_code);
   base::CloseProcessHandle(handle);
 }
 
 }  // namespace