Add tools for code coverage support in iOS.

base/test/test_support_ios.mm

Index: base/test/test_support_ios.mm
diff --git a/base/test/test_support_ios.mm b/base/test/test_support_ios.mm
index d7e99908eaf857b3240cc22aca57eec0dda5d26b..a060e2ea98ef8a836dd1b44c16c31d25b4bab2bc 100644
--- a/base/test/test_support_ios.mm
+++ b/base/test/test_support_ios.mm
@@ -169,7 +169,8 @@ static char** g_argv;
   UIApplication* application = [UIApplication sharedApplication];
   [application _terminateWithStatus:exitStatus];
 
-  coverage_util::FlushCoverageDataIfNecessary();
+  // TODO(lpromero): Enable.
+  //coverage_util::SetupIfNecessary();
 
   exit(exitStatus);
 }