Flush gcda (code coverage) files manually in iOS Platform Test.

testing/platform_test_ios.mm

 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "platform_test.h"
 
 #import <Foundation/Foundation.h>
 
+#include "coverage_util_ios.h"
+
 PlatformTest::PlatformTest()
     : pool_([[NSAutoreleasePool alloc] init]) {
 }
 
 PlatformTest::~PlatformTest() {
   [pool_ release];
+  coverage_util::FlushCoverageDataIfNecessary();
 }