Incorporate BlobChannel into Blimp image encode/decode pipeline.

blimp/engine/renderer/blob_channel_sender_host.cc

+// 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 "blimp/engine/renderer/blob_channel_sender_host.h"
+
+#include "content/public/common/service_registry.h"
+#include "content/public/renderer/render_thread.h"
+
+namespace blimp {
+namespace engine {
+namespace {
+
+mojom::BlobChannelPtr GetConnectedBlobChannel() {
+  mojom::BlobChannelPtr blob_channel_ptr;
+  content::RenderThread::Get()->GetServiceRegistry()->ConnectToRemoteService(
+      mojo::GetProxy(&blob_channel_ptr));
+  CHECK(blob_channel_ptr) << "Could not connect to BlobChannel Mojo service.";
+  return blob_channel_ptr;
+}
+
+}  // namespace
+
+BlobChannelSenderHost::BlobChannelSenderHost()
+    : blob_channel_(GetConnectedBlobChannel()) {}
+
+BlobChannelSenderHost::~BlobChannelSenderHost() {}
+
+int BlobChannelSenderHost::GetReplicationState(const std::string& id) const {
+  if (replication_state_.find(id) == replication_state_.end()) {
+    return 0;
+  } else {
+    return replication_state_.at(id);
+  }
+}
+
+void BlobChannelSenderHost::Put(const std::string& id,
+                                const std::string& data) {
+  // Callers should only call Put() if the blob does not already exist in the
+  // BlobChannel.
+  DCHECK_NE(ReplicationState::ENGINE,
+            GetReplicationState(id) & ReplicationState::ENGINE);

[Wez, 2016/05/21 01:08:04]

This DCHECK_NE is effectively just a bool test; you'd be better off doing a
plain DCHECK.

[Kevin M, 2016/05/27 22:35:30]

Done.

+
+  replication_state_[id] = ReplicationState::ENGINE;
+  blob_channel_->Put(id, data);
+}
+
+void BlobChannelSenderHost::Push(const std::string& id) {
+  // Callers should only call Push() iff the blob is already in the BlobChannel

[Wez, 2016/05/21 01:08:04]

nit: I've been asked in prior reviews not to use "iff" because apparently it's
not well-known.

[Kevin M, 2016/05/27 22:35:30]

Done.

+  // and the client does not already have it.
+  DCHECK_EQ(ReplicationState::ENGINE, GetReplicationState(id));
+
+  // We assume that the client will have the blob if we push it.
+  // TODO(kmarshall): Revisit this assumption when asynchronous blob transport
+  // is supported.
+  replication_state_[id] = replication_state_[id] | ReplicationState::CLIENT;
+
+  blob_channel_->Push(id);
+}
+
+}  // namespace engine
+}  // namespace blimp