Make NGInlineItemsBuilder construct whitespace-collapsed offset mapping

third_party/WebKit/Source/core/layout/ng/api/ng_offset_mapping_builder.cc

Index: third_party/WebKit/Source/core/layout/ng/api/ng_offset_mapping_builder.cc
diff --git a/third_party/WebKit/Source/core/layout/ng/api/ng_offset_mapping_builder.cc b/third_party/WebKit/Source/core/layout/ng/api/ng_offset_mapping_builder.cc
new file mode 100644
index 0000000000000000000000000000000000000000..8f2e03ad62bb120dccdfafb94358d2df06935fc6
--- /dev/null
+++ b/third_party/WebKit/Source/core/layout/ng/api/ng_offset_mapping_builder.cc
@@ -0,0 +1,19 @@
+// 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.
+
+#include "core/layout/ng/api/ng_offset_mapping_builder.h"
+
+namespace blink {
+
+NGOffsetMappingBuilder::NGOffsetMappingBuilder() = default;
+
+NGOffsetMappingBuilder::~NGOffsetMappingBuilder() = default;
+
+void NGOffsetMappingBuilder::AppendBijection(unsigned) {}
+
+void NGOffsetMappingBuilder::AppendCollapsed(unsigned) {}
+
+void NGOffsetMappingBuilder::CollapseLastCharacter() {}
+
+}  // namespace blink