Adds null check for file locations in XML output printer.

include/gtest/internal/gtest-internal.h

@@ -536,20 +536,6 @@ GTEST_API_ AssertionResult IsHRESULTFailure(const char* expr,
 
 #endif  // GTEST_OS_WINDOWS
 
-// Formats a source file path and a line number as they would appear
-// in a compiler error message.
-inline String FormatFileLocation(const char* file, int line) {
-  const char* const file_name = file == NULL ? "unknown file" : file;
-  if (line < 0) {
-    return String::Format("%s:", file_name);
-  }
-#ifdef _MSC_VER
-  return String::Format("%s(%d):", file_name, line);
-#else
-  return String::Format("%s:%d:", file_name, line);
-#endif  // _MSC_VER
-}
-
 // Types of SetUpTestCase() and TearDownTestCase() functions.
 typedef void (*SetUpTestCaseFunc)();
 typedef void (*TearDownTestCaseFunc)();

include/gtest/internal/gtest-port.h

@@ -848,6 +848,16 @@ class GTEST_API_ RE {
   GTEST_DISALLOW_ASSIGN_(RE);
 };
 
+// Formats a source file path and a line number as they would appear
+// in an error message from the compiler used to compile this code.
+GTEST_API_ ::std::string FormatFileLocation(const char* file, int line);
+
+// Formats a file location for compiler-independent XML output.
+// Although this function is not platform dependent, we put it next to
+// FormatFileLocation in order to contrast the two functions.
+GTEST_API_ ::std::string FormatCompilerIndependentFileLocation(const char* file,
+                                                               int line);
+
 // Defines logging utilities:
 //   GTEST_LOG_(severity) - logs messages at the specified severity level. The
 //                          message itself is streamed into the macro.