Chromoting browser-tests should be able to read files specified with relative paths.

chrome/test/remoting/remote_desktop_browsertest.cc

Index: chrome/test/remoting/remote_desktop_browsertest.cc
diff --git a/chrome/test/remoting/remote_desktop_browsertest.cc b/chrome/test/remoting/remote_desktop_browsertest.cc
index cf34624e6956e46b062f18ad1dec5fb12124bc0b..b1d5717fcda55ac6b14875e7534da2038b612598 100644
--- a/chrome/test/remoting/remote_desktop_browsertest.cc
+++ b/chrome/test/remoting/remote_desktop_browsertest.cc
@@ -821,11 +821,19 @@ void RemoteDesktopBrowserTest::DismissHostVersionWarningIfVisible() {
 void RemoteDesktopBrowserTest::SetUserNameAndPassword(
     const base::FilePath &accounts_file_path, const std::string& account_type) {
 
-  // Read contents of accounts file.
-  std::string accounts_info;
-  ASSERT_TRUE(base::ReadFileToString(accounts_file_path, &accounts_info));
+  // ReadFileToString returns an error if the file-path is relative.
+  // Tests that run on the swarming slaves use relative paths, so we have to use
+  // ReadFile instead.
+  int64 accounts_file_size;
+  base::GetFileSize(accounts_file_path, &accounts_file_size);
+  // There is a compile error on Windows if you use a non-constant array size.
+  // For the test-accounts file, we'll assume a maximum file size of 10K.
+  char buf[10240];
+  ASSERT_FALSE(base::ReadFile(accounts_file_path, buf, accounts_file_size - 1)
+    == -1);
 
   // Get the root dictionary from the input json file contents.
+  std::string accounts_info(buf);
   scoped_ptr<base::Value> root(
       base::JSONReader::Read(accounts_info, base::JSON_ALLOW_TRAILING_COMMAS));