Simple Cache: stop running index file tests on Windows

net/disk_cache/backend_unittest.cc

 // Copyright (c) 2012 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 "base/basictypes.h"
 #include "base/file_util.h"
 #include "base/metrics/field_trial.h"
 #include "base/port.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
@@ skipping 3118 matching lines @@
   entry->Close();
   entry = NULL;
   same_entry->Close();
   same_entry = NULL;
 }
 
 TEST_F(DiskCacheBackendTest, TracingBackendBasics) {
   TracingBackendBasics();
 }
 
-// The simple cache backend isn't intended to work on windows, which has very
-// different file system guarantees from Windows.
-#if !defined(OS_WIN)
+// The Simple Cache backend requires a few guarantees from the filesystem like
+// atomic renaming of recently open files. Those guarantees are not provided in
+// general on Windows.
+#if defined(OS_POSIX)
 
 TEST_F(DiskCacheBackendTest, SimpleCacheShutdownWithPendingCreate) {
   SetCacheType(net::APP_CACHE);
   SetSimpleCacheMode();
   BackendShutdownWithPendingCreate(false);
 }
 
 TEST_F(DiskCacheBackendTest, SimpleCacheShutdownWithPendingFileIO) {
   SetCacheType(net::APP_CACHE);
   SetSimpleCacheMode();
@@ skipping 314 matching lines @@
   std::set<std::string> keys_to_match(key_pool);
   void* iter = NULL;
   size_t count = 0;
   ASSERT_TRUE(EnumerateAndMatchKeys(-1, &iter, &keys_to_match, &count));
   cache_->EndEnumeration(&iter);
 
   EXPECT_EQ(key_pool.size(), count);
   EXPECT_TRUE(keys_to_match.empty());
 }
 
-#endif  // !defined(OS_WIN)
+#endif  // defined(OS_POSIX)