Add a size estimation mechanism to StoragePartitionHttpCacheDataRemover.

net/disk_cache/simple/simple_backend_impl.cc

 // Copyright (c) 2013 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 "net/disk_cache/simple/simple_backend_impl.h"
 
 #include <algorithm>
 #include <cstdlib>
 #include <functional>
 
@@ skipping 452 matching lines @@
       base::Bind(&SimpleBackendImpl::IndexReadyForDoom, AsWeakPtr(),
                  initial_time, end_time, callback));
 }
 
 int SimpleBackendImpl::DoomEntriesSince(
     const Time initial_time,
     const CompletionCallback& callback) {
   return DoomEntriesBetween(initial_time, Time(), callback);
 }
 
+int SimpleBackendImpl::CalculateSizeOfEntriesBetween(
+    base::Time initial_time,
+    base::Time end_time,
+    const CompletionCallback& callback) {
+  // TODO(msramek): Implement.

[pasko, 2015/09/04 14:11:50]

for implementation I would suggest to wait for index to get ready:
index_->ExecuteWhenReady() then just go through all 
entries_set_ and ask for GetEntrySize() there.

[msramek, 2015/09/04 16:56:47]

Acknowledged. But if you don't mind, I'll do that in a followup CL. I'll make
sure to include you as a reviewer.

(I want to do each backend separately, but I had to put the infrastructure in
place first)

[pasko, 2015/09/08 13:13:49]

sure, sorry for the confusion, I only wrote it to help with future CL(s)

+  return net::ERR_NOT_IMPLEMENTED;
+}
+
 class SimpleBackendImpl::SimpleIterator final : public Iterator {
  public:
   explicit SimpleIterator(base::WeakPtr<SimpleBackendImpl> backend)
       : backend_(backend),
         weak_factory_(this) {
   }
 
   // From Backend::Iterator:
   int OpenNextEntry(Entry** next_entry,
                     const CompletionCallback& callback) override {
@@ skipping 250 matching lines @@
 }
 
 // static
 void SimpleBackendImpl::FlushWorkerPoolForTesting() {
   // We only need to do this if we there is an active task runner.
   if (base::ThreadTaskRunnerHandle::IsSet())
     g_sequenced_worker_pool.Get().FlushForTesting();
 }
 
 }  // namespace disk_cache