Cache Backend Proxy to intercept all cache events from the IO thread.

net/disk_cache/backend_unittest.cc

Index: net/disk_cache/backend_unittest.cc
diff --git a/net/disk_cache/backend_unittest.cc b/net/disk_cache/backend_unittest.cc
index 0cd754166cd38a5b0e0917f77a6d4aabee00d878..18a70139e2a8f3a8f7efc01ba3e3979655367118 100644
--- a/net/disk_cache/backend_unittest.cc
+++ b/net/disk_cache/backend_unittest.cc
@@ -20,6 +20,7 @@
 #include "net/disk_cache/histogram_macros.h"
 #include "net/disk_cache/mapped_file.h"
 #include "net/disk_cache/mem_backend_impl.h"
+#include "net/disk_cache/tracing_cache_backend.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 #if defined(OS_WIN)
@@ -71,6 +72,7 @@ class DiskCacheBackendTest : public DiskCacheTestWithCache {
   void BackendDisable2();
   void BackendDisable3();
   void BackendDisable4();
+  void TracingBackendBasics();
 };
 
 void DiskCacheBackendTest::BackendBasics() {
@@ -2663,3 +2665,45 @@ TEST_F(DiskCacheBackendTest, ShaderCacheUpdateRankForExternalCacheHit) {
   ASSERT_EQ(net::OK, OpenEntry("key0", &entry));
   entry->Close();
 }
+
+void DiskCacheBackendTest::TracingBackendBasics() {
+  InitCache();
+  cache_ = new disk_cache::TracingCacheBackend(cache_);
+  cache_impl_ = NULL;
+  EXPECT_EQ(net::DISK_CACHE, cache_->GetCacheType());
+  if (!simple_cache_mode_) {
+    EXPECT_EQ(0, cache_->GetEntryCount());
+  }
+
+  net::TestCompletionCallback cb;
+  disk_cache::Entry* entry = NULL;
+  EXPECT_NE(net::OK, OpenEntry("key", &entry));
+  EXPECT_TRUE(NULL == entry);
+
+  ASSERT_EQ(net::OK, CreateEntry("key", &entry));
+  EXPECT_TRUE(NULL != entry);
+
+  disk_cache::Entry* same_entry = NULL;
+  ASSERT_EQ(net::OK, OpenEntry("key", &same_entry));
+  EXPECT_TRUE(NULL != same_entry);
+
+  if (!simple_cache_mode_) {
+    EXPECT_EQ(1, cache_->GetEntryCount());
+  }
+  entry->Close();
+  entry = NULL;
+  same_entry->Close();
+  same_entry = NULL;
+}
+
+#ifdef USE_TRACING_CACHE_BACKEND

[rvargas (doing something else), 2013/04/05 19:25:13]

This has no relation with the active defines for the net target, so it seems
pointless.

[pasko-google - do not use, 2013/04/08 15:37:40]

This guards against someone trying to run tests with the tracing backend always
on, which may reveal obscure bugs that I do not want anyone to step in. I am OK
removing it or enhancing with a comment that would clarify the intentions.

+#error "The tracing backend should be created manually in tests"
+#endif
+TEST_F(DiskCacheBackendTest, TracingBackendBasicsWithBackendImpl) {
+  TracingBackendBasics();
+}
+
+TEST_F(DiskCacheBackendTest, TracingBackendBasicsWithSimpleBackend) {
+  SetSimpleCacheMode();
+  TracingBackendBasics();
+}