Fix modules_unittests on iOS.

webrtc/test/testsupport/iosfileutils.mm

 /*
  *  Copyright 2015 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 36 matching lines @@
     NSString* path = NSStringFromStdString(name);
     NSString* fileName = path.lastPathComponent;
     NSString* fileType = NSStringFromStdString(extension);
     // Get full pathname for the resource identified by the name and extension.
     NSString* pathString = [[NSBundle mainBundle] pathForResource:fileName
                                                            ofType:fileType];
     return StdStringFromNSString(pathString);
   }
 }
 
+std::string IOSRootPath() {
+  @autoreleasepool {
+    NSBundle* mainBundle = [NSBundle mainBundle];
+    return StdStringFromNSString(mainBundle.bundlePath) + "/";
+  }
+}
+
 // For iOS, we don't have access to the output directory. Return the path to the
 // temporary directory instead. This is mostly used by tests that need to write
 // output files to disk.
 std::string IOSOutputPath()  {
   @autoreleasepool {
     NSString* tempDir = NSTemporaryDirectory();
     if (tempDir == nil)
         tempDir = @"/tmp";
     return StdStringFromNSString(tempDir);
   }
 }
 
 }  // namespace test
 }  // namespace webrtc
 
 #endif  // defined(WEBRTC_IOS)