[ios] Moved WebUI provider code to ios/web.

ios/public/provider/web/web_ui_ios_message_handler.cc

-// Copyright 2014 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 "ios/public/provider/web/web_ui_ios_message_handler.h"
-
-#include "base/logging.h"
-#include "base/strings/string_number_conversions.h"
-#include "base/strings/utf_string_conversions.h"
-#include "base/values.h"
-
-namespace web {
-
-bool WebUIIOSMessageHandler::ExtractIntegerValue(const base::ListValue* value,
-                                                 int* out_int) {
-  std::string string_value;
-  if (value->GetString(0, &string_value))
-    return base::StringToInt(string_value, out_int);
-  double double_value;
-  if (value->GetDouble(0, &double_value)) {
-    *out_int = static_cast<int>(double_value);
-    return true;
-  }
-  NOTREACHED();
-  return false;
-}
-
-bool WebUIIOSMessageHandler::ExtractDoubleValue(const base::ListValue* value,
-                                                double* out_value) {
-  std::string string_value;
-  if (value->GetString(0, &string_value))
-    return base::StringToDouble(string_value, out_value);
-  if (value->GetDouble(0, out_value))
-    return true;
-  NOTREACHED();
-  return false;
-}
-
-base::string16 WebUIIOSMessageHandler::ExtractStringValue(
-    const base::ListValue* value) {
-  base::string16 string16_value;
-  if (value->GetString(0, &string16_value))
-    return string16_value;
-  NOTREACHED();
-  return base::string16();
-}
-
-}  // namespace web