Add a size estimation mechanism to StoragePartitionHttpCacheDataRemover.

net/disk_cache/blockfile/backend_impl.cc

Index: net/disk_cache/blockfile/backend_impl.cc
diff --git a/net/disk_cache/blockfile/backend_impl.cc b/net/disk_cache/blockfile/backend_impl.cc
index 50e7b026a83e4b199a3c893f0eae18655e1f5912..4e3b7a958f9aa91fa5c169e3fd87560daec7925e 100644
--- a/net/disk_cache/blockfile/backend_impl.cc
+++ b/net/disk_cache/blockfile/backend_impl.cc
@@ -436,6 +436,40 @@ int BackendImpl::SyncDoomEntriesSince(const base::Time initial_time) {
   }
 }
 
+int BackendImpl::SyncCalculateSizeOfEntriesBetween(
+    const base::Time initial_time, const base::Time end_time) {
+  DCHECK_NE(net::APP_CACHE, cache_type_);
+  DCHECK_GE(end_time, initial_time);
+  if (disabled_)
+    return net::ERR_FAILED;
+
+  EntryImpl* node;
+  scoped_ptr<Rankings::Iterator> iterator(new Rankings::Iterator());
+  EntryImpl* next = OpenNextEntryImpl(iterator.get());
+  if (!next)
+    return net::OK;
+
+  int size = 0;
+  while (next) {
+    node = next;
+    next = OpenNextEntryImpl(iterator.get());
+
+    if (node->GetLastUsed() >= initial_time &&
+        node->GetLastUsed() < end_time) {
+      size += node->GetEntrySize();
+    } else if (node->GetLastUsed() < initial_time) {
+      if (next)
+        next->Release();
+      next = NULL;
+      SyncEndEnumeration(iterator.Pass());
+    }
+
+    node->Release();
+  }
+
+  return size;
+}
+
 int BackendImpl::SyncOpenNextEntry(Rankings::Iterator* iterator,
                                    Entry** next_entry) {
   *next_entry = OpenNextEntryImpl(iterator);
@@ -1254,6 +1288,16 @@ int BackendImpl::DoomEntriesSince(const base::Time initial_time,
   return net::ERR_IO_PENDING;
 }
 
+int BackendImpl::CalculateSizeOfEntriesBetween(
+    base::Time initial_time,
+    base::Time end_time,
+    const CompletionCallback& callback) {
+  DCHECK(!callback.is_null());
+  background_queue_.CalculateSizeOfEntriesBetween(
+      initial_time, end_time, callback);
+  return net::ERR_IO_PENDING;
+}
+
 class BackendImpl::IteratorImpl : public Backend::Iterator {
  public:
   explicit IteratorImpl(base::WeakPtr<InFlightBackendIO> background_queue)