Fixed "blocking io" from FixupPath on UI thread.

chrome/browser/printing/print_preview_pdf_generated_browsertest.cc

 // Copyright 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.
 
 #include <algorithm>
 #include <fstream>
 #include <iostream>
 #include <iterator>
 #include <limits>
 #include <string>
@@ skipping 289 matching lines @@
  public:
   PrintPreviewPdfGeneratedBrowserTest() {}
   ~PrintPreviewPdfGeneratedBrowserTest() override {}
 
   // Navigates to the given web page, then initiates print preview and waits
   // for all the settings to be set, then save the preview to PDF.
   void NavigateAndPrint(const base::FilePath::StringType& file_name,
                           const PrintPreviewSettings& settings) {
     print_preview_observer_->SetPrintPreviewSettings(settings);
     base::FilePath path(file_name);
-    GURL gurl = net::FilePathToFileURL(path);
+    GURL gurl = net::FilePathToFileURL(base::MakeAbsoluteFilePath(path));
 
     ui_test_utils::NavigateToURL(browser(), gurl);
 
     base::RunLoop loop;
     print_preview_observer_->set_quit_closure(loop.QuitClosure());
     chrome::Print(browser());
     loop.Run();
 
     // Need to check whether the save was successful. Ending the loop only
     // means the save was attempted.
@@ skipping 309 matching lines @@
     // waiting for this message and start waiting for the image data.
     std::cout << "#EOF\n";
     std::cout.flush();
 
     SendPng();
     Reset();
   }
 }
 
 }  // namespace printing