[IndexedDB] Adding txn, value, and key size metrics

third_party/WebKit/Source/modules/indexeddb/IDBValueWrapping.h

 // Copyright 2017 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 IDBValueWrapping_h
 #define IDBValueWrapping_h
 
 #include "bindings/core/v8/ExceptionState.h"
 #include "bindings/core/v8/serialization/SerializedScriptValue.h"
 #include "modules/ModulesExport.h"
@@ skipping 93 matching lines @@
   // This method must be called at most once, and must be called after
   // WrapIfBiggerThan().
   inline Vector<WebBlobInfo>& WrappedBlobInfo() {
 #if DCHECK_IS_ON()
     DCHECK(!had_exception_)
         << "WrapBlobInfo() called on wrapper with serialization exception";
 #endif  // DCHECK_IS_ON()
     return blob_info_;
   }
 
+  size_t DataLengthBeforeWrapInBytes() { return original_data_length_; }
+
   // Default threshold for WrapIfBiggerThan().
   //
   // This should be tuned to achieve a compromise between short-term IndexedDB
   // throughput and long-term I/O load and memory usage. LevelDB, the underlying
   // storage for IndexedDB, was not designed with large values in mind. At the
   // very least, large values will slow down compaction, causing occasional I/O
   // spikes.
   static constexpr unsigned kWrapThreshold = 64 * 1024;
 
   // MIME type used for Blobs that wrap IDBValues.
   static constexpr const char* kWrapMimeType =
       "application/vnd.blink-idb-value-wrapper";
 
  private:
   // Used to serialize the wrapped value.
   static void WriteVarint(unsigned value, Vector<char>& output);
 
   RefPtr<SerializedScriptValue> serialized_value_;
   RefPtr<BlobDataHandle> wrapper_handle_;
   Vector<WebBlobInfo> blob_info_;
   Vector<char> wire_bytes_;
+  size_t original_data_length_ = 0;
 #if DCHECK_IS_ON()
   bool had_exception_ = false;
   bool wrap_called_ = false;
 #endif  // DCHECK_IS_ON()
 };
 
 // State and logic for unwrapping large IndexedDB values from Blobs.
 //
 // See IDBValueWrapper for an explanation of the wrapping concept.
 //
@@ skipping 60 matching lines @@
   // The size of the Blob holding the data for the last unwrapped IDBValue.
   unsigned blob_size_;
 
   // Handle to the Blob holding the data for the last unwrapped IDBValue.
   RefPtr<BlobDataHandle> blob_handle_;
 };
 
 }  // namespace blink
 
 #endif  // IDBValueWrapping_h