Precache manifest should not be added to fetcher pool which is full

components/precache/core/fetcher_pool.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 COMPONENTS_PRECACHE_CORE_FETCHER_POOL_H_
 #define COMPONENTS_PRECACHE_CORE_FETCHER_POOL_H_
 
 #include <memory>
 #include <unordered_map>
 
+#include "base/gtest_prod_util.h"
 #include "base/logging.h"
 
 namespace precache {
 
 // FetcherPool that accepts a limited number of elements.
 //
 // FetcherPool is particularly suited for having multiple URLFetchers running
 // in parallel.
 //
 // It doesn't enqueue the elements above a defined capacity. The callsite must
@@ skipping 43 matching lines @@
   // Returns true iff the pool is empty.
   bool IsEmpty() const { return elements_.empty(); }
 
   // Returns true iff the pool can accept a new element.
   bool IsAvailable() const { return max_size_ > elements_.size(); }
 
   const std::unordered_map<const T*, std::unique_ptr<T>>& elements() const {
     return elements_;
   }
 
+  // Returns the maximum size of the pool.
+  size_t max_size() const { return max_size_; }
+
  private:
   const size_t max_size_;
   std::unordered_map<const T*, std::unique_ptr<T>> elements_;
 
   DISALLOW_COPY_AND_ASSIGN(FetcherPool);
 };
 
 }  // namespace precache
 
 #endif  // COMPONENTS_PRECACHE_CORE_FETCHER_POOL_H_