Inform disk cache of WebKit memory cache hits.

net/disk_cache/backend_unittest.cc

 // Copyright (c) 2011 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/string_util.h"
 #include "base/stringprintf.h"
 #include "base/third_party/dynamic_annotations/dynamic_annotations.h"
 #include "base/threading/platform_thread.h"
@@ skipping 2100 matching lines @@
   char buffer1[kSize];
   char buffer2[kSize];
   memset(buffer1, 't', kSize);
   memset(buffer2, 0, kSize);
   EXPECT_TRUE(file->Write(buffer1, kSize, 0));
   EXPECT_TRUE(file->Read(buffer2, kSize, 0));
   EXPECT_EQ(0, memcmp(buffer1, buffer2, kSize));
 
   EXPECT_TRUE(disk_cache::DeleteCacheFile(name));
 }
+
+TEST_F(DiskCacheBackendTest, UpdateRankForExternalCacheHit) {
+  SetDirectMode();
+  InitCache();
+
+  disk_cache::Entry* entry;
+
+  for (int i = 0; i < 2; ++i) {
+    std::string key = StringPrintf("key%d", i);
+    ASSERT_EQ(net::OK, CreateEntry(key, &entry));
+    entry->Close();
+  }
+
+  // Ping the oldest entry.
+  cache_->OnExternalCacheHit("key0");
+
+  TrimForTest(false);
+
+  // Make sure the older key remains.
+  EXPECT_EQ(1, cache_->GetEntryCount());
+  ASSERT_EQ(net::OK, OpenEntry("key0", &entry));
+  entry->Close();
+}