PrintPreviewPdfGeneratedBrowserTest properly listens to messages and exits correctly.

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 634 matching lines @@
   SetupStdinAndSavePath();
 
   // There is no way to determine how many tests are to be run ahead of time
   // without undesirable changes to the layout test framework. However, that is
   // ok since whenever all the tests have been run, the layout test framework
   // calls SIGKILL on this process, ending the test. This will end the while
   // loop and cause the test to clean up after itself. For this to work, the
   // browsertest must be run with '--single_process' not '--single-process.'
   while (true) {
     std::string input;
-    std::getline(std::cin, input);

[ivandavid, 2014/07/23 03:33:57]

The error would occur after at least 1 iteration of the loop starting at 653.
The problem was that |input| would be empty,  yet |std::cin.eof()| would
evaluate to false, causing the loop to exit when it shouldn't have. To prevent
this, the loop exits when |input| is empty and just keeps clearing the state of
|std::cin| since eventually the input will be correct. |input| is guaranteed to
either be empty or have the correct input due to how the layout test framework
prints everything so this works.

-    if (input.empty()) {
-      while (std::cin.eof()) {
+    while (input.empty()) {
+      if (std::cin.eof())
         std::cin.clear();
-        std::getline(std::cin, input);
-        if (!input.empty()) {
-          break;
-        }
-      }
+      std::getline(std::cin, input);
     }
 
     base::FilePath::StringType file_extension = FILE_PATH_LITERAL(".pdf");
     base::FilePath::StringType cmd;
 #if defined(OS_POSIX)
     cmd = input;
 #elif defined(OS_WIN)
     cmd = base::UTF8ToWide(input);
 #endif
 
@@ skipping 24 matching lines @@
     // waiting for this message and start waiting for the image data.
     std::cout << "#EOF\n";
     std::cout.flush();
 
     SendPng();
     Reset();
   }
 }
 
 }  // namespace printing