Update from https://crrev.com/327068

base/json/json_value_converter.h

Index: base/json/json_value_converter.h
diff --git a/base/json/json_value_converter.h b/base/json/json_value_converter.h
index c4bfe61e9d38a5056951efd27e6a45d3a5bb570c..f94d46e3ccf71cbd7a19aeef0c608dcd17b14a06 100644
--- a/base/json/json_value_converter.h
+++ b/base/json/json_value_converter.h
@@ -123,8 +123,7 @@ class FieldConverter : public FieldConverterBase<StructType> {
         value_converter_(converter) {
   }
 
-  virtual bool ConvertField(
-      const base::Value& value, StructType* dst) const override {
+  bool ConvertField(const base::Value& value, StructType* dst) const override {
     return value_converter_->Convert(value, &(dst->*field_pointer_));
   }
 
@@ -202,8 +201,7 @@ class ValueFieldConverter : public ValueConverter<FieldType> {
   ValueFieldConverter(ConvertFunc convert_func)
       : convert_func_(convert_func) {}
 
-  virtual bool Convert(const base::Value& value,
-                       FieldType* field) const override {
+  bool Convert(const base::Value& value, FieldType* field) const override {
     return convert_func_(&value, field);
   }
 
@@ -221,8 +219,7 @@ class CustomFieldConverter : public ValueConverter<FieldType> {
   CustomFieldConverter(ConvertFunc convert_func)
       : convert_func_(convert_func) {}
 
-  virtual bool Convert(const base::Value& value,
-                       FieldType* field) const override {
+  bool Convert(const base::Value& value, FieldType* field) const override {
     std::string string_value;
     return value.GetAsString(&string_value) &&
         convert_func_(string_value, field);
@@ -239,8 +236,7 @@ class NestedValueConverter : public ValueConverter<NestedType> {
  public:
   NestedValueConverter() {}
 
-  virtual bool Convert(
-      const base::Value& value, NestedType* field) const override {
+  bool Convert(const base::Value& value, NestedType* field) const override {
     return converter_.Convert(value, field);
   }
 
@@ -254,8 +250,8 @@ class RepeatedValueConverter : public ValueConverter<ScopedVector<Element> > {
  public:
   RepeatedValueConverter() {}
 
-  virtual bool Convert(
-      const base::Value& value, ScopedVector<Element>* field) const override {
+  bool Convert(const base::Value& value,
+               ScopedVector<Element>* field) const override {
     const base::ListValue* list = NULL;
     if (!value.GetAsList(&list)) {
       // The field is not a list.
@@ -290,8 +286,8 @@ class RepeatedMessageConverter
  public:
   RepeatedMessageConverter() {}
 
-  virtual bool Convert(const base::Value& value,
-                       ScopedVector<NestedType>* field) const override {
+  bool Convert(const base::Value& value,
+               ScopedVector<NestedType>* field) const override {
     const base::ListValue* list = NULL;
     if (!value.GetAsList(&list))
       return false;
@@ -327,8 +323,8 @@ class RepeatedCustomValueConverter
   RepeatedCustomValueConverter(ConvertFunc convert_func)
       : convert_func_(convert_func) {}
 
-  virtual bool Convert(const base::Value& value,
-                       ScopedVector<NestedType>* field) const override {
+  bool Convert(const base::Value& value,
+               ScopedVector<NestedType>* field) const override {
     const base::ListValue* list = NULL;
     if (!value.GetAsList(&list))
       return false;