[BlobStorage] Fix UMA reporting.

storage/browser/blob/blob_storage_context.cc

Index: storage/browser/blob/blob_storage_context.cc
diff --git a/storage/browser/blob/blob_storage_context.cc b/storage/browser/blob/blob_storage_context.cc
index 01faea71033edc314ae19711cfcfadda00bbf6aa..1fecda89f5b6799136cab3bc4089840251ad8f3b 100644
--- a/storage/browser/blob/blob_storage_context.cc
+++ b/storage/browser/blob/blob_storage_context.cc
@@ -297,8 +297,6 @@ BlobStorageContext::BlobSlice::BlobSlice(const BlobEntry& source,
             source_item->expected_modification_time());
         data_item =
             new BlobDataItem(std::move(element), source_item->data_handle_);
-        UMA_HISTOGRAM_COUNTS("Storage.BlobItemSize.BlobSlice.Bytes",
-                             read_size / 1024);
 
         DCHECK(!BlobDataBuilder::IsFutureFileItem(source_item->data_element()))
             << "File allocation unimplemented.";
@@ -315,6 +313,8 @@ BlobStorageContext::BlobSlice::BlobSlice(const BlobEntry& source,
         break;
       }
       case DataElement::TYPE_DISK_CACHE_ENTRY: {
+        UMA_HISTOGRAM_COUNTS("Storage.BlobItemSize.BlobSlice.CacheEntry",
+                             read_size / 1024);
         std::unique_ptr<DataElement> element(new DataElement());
         element->SetToDiskCacheEntryRange(source_item->offset() + item_offset,
                                           read_size);