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

blimp/common/blob_cache/mock_blob_cache.h

 // 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_COMMON_BLOB_CACHE_MOCK_BLOB_CACHE_H_
 #define BLIMP_COMMON_BLOB_CACHE_MOCK_BLOB_CACHE_H_
 
+#include <vector>
+
 #include "blimp/common/blob_cache/blob_cache.h"
 #include "testing/gmock/include/gmock/gmock.h"
 
 namespace blimp {
 
 class MockBlobCache : public BlobCache {
  public:
   MockBlobCache();
   ~MockBlobCache() override;
 
   MOCK_CONST_METHOD1(Contains, bool(const BlobId&));
   MOCK_METHOD2(Put, void(const BlobId&, BlobDataPtr));
   MOCK_CONST_METHOD1(Get, BlobDataPtr(const BlobId&));
+  MOCK_CONST_METHOD0(GetCachedBlobIds, std::vector<BlobId>());
 
  private:
   DISALLOW_COPY_AND_ASSIGN(MockBlobCache);
 };
 
 }  // namespace blimp
 
 #endif  // BLIMP_COMMON_BLOB_CACHE_MOCK_BLOB_CACHE_H_