Incorporate BlobChannel into Blimp image encode/decode pipeline.

blimp/engine/renderer/blob_channel_sender_proxy.h

Index: blimp/engine/renderer/blob_channel_sender_proxy.h
diff --git a/blimp/engine/renderer/blob_channel_sender_proxy.h b/blimp/engine/renderer/blob_channel_sender_proxy.h
new file mode 100644
index 0000000000000000000000000000000000000000..e219ef06c35e7ff5fda51bed6f00343a4bd8ceb7
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+++ b/blimp/engine/renderer/blob_channel_sender_proxy.h
@@ -0,0 +1,52 @@
+// 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.
+
+#ifndef BLIMP_ENGINE_RENDERER_BLOB_CHANNEL_SENDER_PROXY_H_
+#define BLIMP_ENGINE_RENDERER_BLOB_CHANNEL_SENDER_PROXY_H_
+
+#include <memory>
+#include <string>
+
+#include "base/containers/hash_tables.h"
+#include "blimp/common/blimp_common_export.h"
+#include "blimp/engine/mojo/blob_channel.mojom.h"
+#include "blimp/net/blob_channel/blob_channel_sender.h"
+
+namespace blimp {
+namespace engine {
+
+// Class for sending blobs (e.g. images) from the renderer to the browser
+// process.
+class BLIMP_COMMON_EXPORT BlobChannelSenderProxy : public BlobChannelSender {
+ public:
+  BlobChannelSenderProxy();
+  ~BlobChannelSenderProxy() override;
+
+  // Returns true if the blob is known to exist within the Engine cache.
+  bool IsInEngineCache(const std::string& id) const;
+
+  // Returns true if the blob has been delivered to the Client cache.
+  bool IsInClientCache(const std::string& id) const;
+
+  // BlobChannelSender implementation.
+  void PutBlob(const BlobId& id, BlobDataPtr data) override;
+  void DeliverBlob(const BlobId& id) override;
+
+ private:
+  // BlobChannel Mojo IPC stub, used for delivering blobs to the browser
+  // process.
+  mojom::BlobChannelPtr blob_channel_;
+
+  // Local copy of the cache state for the local and remote BlobChannel.
+  // Knowledge of the cache state enables callers to avoid unnecessary
+  // image encoding and transferral if the content is already in the system.
+  base::hash_map<std::string, bool> replication_state_;
+
+  DISALLOW_COPY_AND_ASSIGN(BlobChannelSenderProxy);
+};
+
+}  // namespace engine
+}  // namespace blimp
+
+#endif  // BLIMP_ENGINE_RENDERER_BLOB_CHANNEL_SENDER_PROXY_H_