Add a size estimation mechanism to StoragePartitionHttpCacheDataRemover.

content/browser/cache_storage/cache_storage_cache_unittest.cc

Index: content/browser/cache_storage/cache_storage_cache_unittest.cc
diff --git a/content/browser/cache_storage/cache_storage_cache_unittest.cc b/content/browser/cache_storage/cache_storage_cache_unittest.cc
index 88363a7c4d910dc55512b8ad02fd2a51723b6de4..62e799521481f5e576c14f3b4d4a62a0dd828204 100644
--- a/content/browser/cache_storage/cache_storage_cache_unittest.cc
+++ b/content/browser/cache_storage/cache_storage_cache_unittest.cc
@@ -91,6 +91,10 @@ class DelayableBackend : public disk_cache::Backend {
                        const CompletionCallback& callback) override {
     return backend_->DoomEntriesSince(initial_time, callback);
   }
+  int CalculateSizeOfAllEntries(
+      const CompletionCallback& callback) override {
+    return backend_->CalculateSizeOfAllEntries(callback);
+  }
   scoped_ptr<Iterator> CreateIterator() override {
     return backend_->CreateIterator();
   }