Reserve Vector's capacity manually in CachedMetadata

third_party/WebKit/Source/core/fetch/CachedMetadata.cpp

+// Copyright 2016 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 "core/fetch/CachedMetadata.h"
+
+namespace blink {
+
+CachedMetadata::CachedMetadata(const char* data, size_t size)
+{
+    // We need to define a local variable to use the constant in DCHECK.
+    constexpr auto kDataStart = CachedMetadata::kDataStart;
+    // Serialized metadata should have non-empty data.
+    DCHECK_GT(size, kDataStart);
+    DCHECK(data);
+
+    m_serializedData.reserveInitialCapacity(size);
+    m_serializedData.append(data, size);
+}
+
+CachedMetadata::CachedMetadata(uint32_t dataTypeID, const char* data, size_t size)
+{
+    // Don't allow an ID of 0, it is used internally to indicate errors.
+    DCHECK(dataTypeID);
+    DCHECK(data);
+
+    m_serializedData.reserveInitialCapacity(sizeof(uint32_t) + size);
+    m_serializedData.append(reinterpret_cast<const char*>(&dataTypeID), sizeof(uint32_t));
+    m_serializedData.append(data, size);
+}
+
+} // namespace blink