Add Mojo IPC for seeding new Renderer with Browser's cached blob state.

blimp/net/blob_channel/blob_channel_sender_impl.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/net/blob_channel/blob_channel_sender_impl.h"
 
+#include <utility>
+
+#include "base/stl_util.h"
 #include "base/strings/string_number_conversions.h"
 #include "blimp/common/blob_cache/blob_cache.h"
 #include "blimp/common/blob_cache/id_util.h"
 
 namespace blimp {
 
 BlobChannelSenderImpl::BlobChannelSenderImpl(std::unique_ptr<BlobCache> cache,
                                              std::unique_ptr<Delegate> delegate)
     : cache_(std::move(cache)), delegate_(std::move(delegate)) {
   DCHECK(cache_);
   DCHECK(delegate_);
 }
 
 BlobChannelSenderImpl::~BlobChannelSenderImpl() {}
 
+std::vector<BlobChannelSender::CacheStateEntry>
+BlobChannelSenderImpl::GetCachedBlobIds() const {
+  const auto cache_state = cache_->GetCachedBlobIds();
+  std::vector<CacheStateEntry> output;
+  output.reserve(cache_state.size());
+  for (const std::string& cached_id : cache_state) {
+    CacheStateEntry next_output;
+    next_output.id = cached_id;
+    next_output.was_delivered =
+        ContainsKey(receiver_cache_contents_, cached_id);
+    output.push_back(next_output);
+  }
+  return output;
+}
+
 void BlobChannelSenderImpl::PutBlob(const BlobId& id, BlobDataPtr data) {
   DCHECK(data);
   DCHECK(!id.empty());
 
   if (cache_->Contains(id)) {
     return;
   }
 
   VLOG(2) << "Put blob: " << BlobIdToString(id);
   cache_->Put(id, data);
 }
 
 void BlobChannelSenderImpl::DeliverBlob(const BlobId& id) {
   if (!cache_->Contains(id)) {
     DLOG(FATAL) << "Attempted to push unknown blob: " << BlobIdToString(id);
     return;
   }
 
   if (receiver_cache_contents_.find(id) != receiver_cache_contents_.end()) {
     DVLOG(3) << "Suppressed redundant push: " << BlobIdToString(id);
     return;
   }
   receiver_cache_contents_.insert(id);
 
   VLOG(2) << "Deliver blob: " << BlobIdToString(id);
   delegate_->DeliverBlob(id, cache_->Get(id));
 }
 
 }  // namespace blimp