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

blimp/common/blob_cache/in_memory_blob_cache.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/common/blob_cache/in_memory_blob_cache.h"
 
+#include <utility>
+
 #include "base/logging.h"
 
 namespace blimp {
 
 InMemoryBlobCache::InMemoryBlobCache() {}
 
 InMemoryBlobCache::~InMemoryBlobCache() {}
 
+std::vector<BlobId> InMemoryBlobCache::GetCachedBlobIds() const {
+  std::vector<BlobId> cached_ids;
+  for (const auto& blob_id_and_data_pair : cache_) {
+    cached_ids.push_back(blob_id_and_data_pair.first);
+  }
+  return cached_ids;
+}
+
 void InMemoryBlobCache::Put(const BlobId& id, BlobDataPtr data) {
   if (Contains(id)) {
     // In cases where the engine has miscalculated what is already available
     // on the client, Put() might be called unnecessarily, which should be
     // ignored.
     VLOG(2) << "Item with ID " << id << " already exists in cache.";
     return;
   }
   cache_.insert(std::make_pair(id, std::move(data)));
 }
 
 bool InMemoryBlobCache::Contains(const BlobId& id) const {
   return cache_.find(id) != cache_.end();
 }
 
 BlobDataPtr InMemoryBlobCache::Get(const BlobId& id) const {
   if (!Contains(id)) {
     return nullptr;
   }
 
   return cache_.find(id)->second;
 }
 
 }  // namespace blimp