[ON HOLD] Implement pull-based design for content decoding

net/filter/mock_stream_source.h

Index: net/filter/mock_stream_source.h
diff --git a/net/filter/mock_stream_source.h b/net/filter/mock_stream_source.h
new file mode 100644
index 0000000000000000000000000000000000000000..6ea6bfda18c96f7175082c665fb299c252eb7236
--- /dev/null
+++ b/net/filter/mock_stream_source.h
@@ -0,0 +1,50 @@
+// Copyright 2016 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 <queue>
+
+#include "net/filter/stream_source.h"
+
+namespace net {
+
+class MockStreamSource : public StreamSource {
+ public:
+  MockStreamSource();
+  ~MockStreamSource() override;
+
+  // Testing helpers
+  // Enqueues a result to be returned by |Read|. This method does not make a
+  // copy of |data|, so |data| must outlive this object. If |sync| is true,
+  // |Read| will return the supplied data synchronously; otherwise, the user of
+  // this class needs to call |CompleteNextRead|.
+  void AddReadResult(const char* data, size_t len, Error error, bool sync);
+
+  // Completes a pending Read() call.
+  void CompleteNextRead();
+
+  // StreamSource implementation
+  net::Error Read(IOBuffer* dest_buffer,
+                  size_t buffer_size,
+                  size_t* bytes_read,
+                  const OnReadCompleteCallback& callback) override;
+  size_t GetBytesOutput() const override;
+
+ private:
+  struct QueuedResult {
+    QueuedResult(const char* data, size_t len, Error error, bool sync);
+    const char* data;
+    size_t len;
+    Error error;
+    bool sync;
+  };
+
+  std::queue<QueuedResult> results_;
+  bool awaiting_completion_;
+  IOBuffer* dest_buffer_;
+  size_t dest_buffer_size_;
+  OnReadCompleteCallback callback_;
+  size_t total_bytes_output_;
+};
+
+}  // namespace net