[net] Better StopCaching() handling for HttpCache::Transaction.

net/http/mock_http_cache.h

Index: net/http/mock_http_cache.h
diff --git a/net/http/mock_http_cache.h b/net/http/mock_http_cache.h
index 632bb3e63c16996290e5ed945c6d7f7909eea5c0..57f43a9a6f1e49b78c2958d619dd7cda14185ac0 100644
--- a/net/http/mock_http_cache.h
+++ b/net/http/mock_http_cache.h
@@ -137,6 +137,10 @@ class MockDiskCache : public disk_cache::Backend {
   // Returns number of times a cache entry was successfully created.
   int create_count() const { return create_count_; }
 
+  // Resets open_count() and create_count(). Calling this is recommended to
+  // reset the counts after test setup.
+  void ResetCounts();
+
   // Fail any subsequent CreateEntry and OpenEntry.
   void set_fail_requests() { fail_requests_ = true; }