[Extensions Bindings] Add argument parsing errors

extensions/renderer/api_invocation_errors.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 EXTENSIONS_RENDERER_API_INVOCATION_ERRORS_H_
+#define EXTENSIONS_RENDERER_API_INVOCATION_ERRORS_H_
+
+#include <string>
+
+#include "base/strings/string_piece.h"
+
+// A collection of error-related strings and utilities for parsing API
+// invocations.
+namespace extensions {
+namespace api_errors {
+
+// Strings for the expected types.
+extern const char kTypeString[];
+extern const char kTypeDouble[];
+extern const char kTypeBoolean[];
+extern const char kTypeInteger[];
+extern const char kTypeObject[];
+extern const char kTypeList[];
+extern const char kTypeBinary[];
+extern const char kTypeFunction[];
+extern const char kTypeUndefined[];
+extern const char kTypeNull[];
+
+// Different errors that come up during argument parsing. Note: these messages
+// often hold placeholders for printf; see the .cc file.
+extern const char kInvalidEnumValue[];
+extern const char kMissingRequiredProperty[];
+extern const char kUnexpectedProperty[];
+extern const char kTooFewArrayItems[];
+extern const char kTooManyArrayItems[];
+extern const char kTooFewStringChars[];
+extern const char kTooManyStringChars[];
+extern const char kNumberTooSmall[];
+extern const char kNumberTooLarge[];
+extern const char kInvalidType[];
+extern const char kNotAnInstance[];
+extern const char kInvalidChoice[];
+extern const char kUnserializableValue[];
+extern const char kScriptThrewError[];
+
+// Utility methods to get a formatted error message.
+std::string GetError(const char* error, int placeholder);
+std::string GetError(const char* error, const char* placeholder);
+std::string GetError(const char* error,
+                     const char* placeholder1,
+                     const char* placeholder2);
+
+// Returns an message indicating an error was found while parsing a given index
+// in an array.
+std::string GetIndexError(uint32_t index, base::StringPiece error);
+
+// Returns a message indicating that an error was found while parsing a given
+// property on an object.
+std::string GetPropertyError(base::StringPiece property_name,
+                             base::StringPiece error);
+
+}  // namespace api_errors
+}  // namespace extensions
+
+#endif  // EXTENSIONS_RENDERER_API_INVOCATION_ERRORS_H_