Add NSLogTestEventListener to support running tests on iOS 6 devices.

base/test/test_listener_ios.mm

Index: base/test/test_listener_ios.mm
diff --git a/base/test/test_listener_ios.mm b/base/test/test_listener_ios.mm
index 12cf5bb9ebaaf3a9a5b3a7d719de431e16f3976d..b3399a571b9d23676939570e498761479861b201 100644
--- a/base/test/test_listener_ios.mm
+++ b/base/test/test_listener_ios.mm
@@ -6,7 +6,9 @@
 
 #import <Foundation/Foundation.h>
 
+#include "base/ios/ios_util.h"
 #include "base/mac/scoped_nsautorelease_pool.h"
+#include "base/test/nslog_test_event_listener.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 // The iOS watchdog timer will kill an app that doesn't spin the main event
@@ -41,5 +43,18 @@ void RegisterTestEndListener() {
   listeners.Append(new IOSRunLoopListener);
 }
 
+// Only add the NSLogTestEventListener when running on a device with iOS 6 or
+// later.
+void RegisterNSLogListenerIfNecessary() {
+#if !TARGET_IPHONE_SIMULATOR
+  NSLog(@"Running on a device");
+  if (ios::IsRunningOnIOS6OrLater()) {
+    testing::TestEventListeners& listeners =
+        testing::UnitTest::GetInstance()->listeners();
+    listeners.Append(new NSLogTestEventListener);
+  }
+#endif
+}
+
 }  // namespace test_listener_ios
 }  // namespace base