Move the parsing of "chrome_url_overrides" out of Extension.

chrome/common/extensions/api/url_overrides/url_overrides_handler.h

+// Copyright (c) 2012 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 CHROME_COMMON_EXTENSIONS_API_URL_OVERRIDES_URL_OVERRIDES_HANDLER_H_
+#define CHROME_COMMON_EXTENSIONS_API_URL_OVERRIDES_URL_OVERRIDES_HANDLER_H_
+
+#include <string>
+
+#include "chrome/common/extensions/extension.h"
+#include "chrome/common/extensions/manifest_handler.h"
+
+namespace extensions {
+
+class Extension;
+
+struct URLOverridesInfo : public Extension::ManifestData {
+
+typedef std::map<const std::string, GURL> URLOverrideMap;
+
+  // A map of chrome:// hostnames (newtab, downloads, etc.) to Extension URLs
+  // which override the handling of those URLs. (see ExtensionOverrideUI).
+  URLOverrideMap chrome_url_overrides_;
+
+  static const URLOverrideMap GetChromeURLOverrides(const Extension* extension);

[Joe Thomas, 2012/12/29 14:44:28]

I think it's better to pass a pointer to URLOverridesInfo to avoid making a copy
and handle the null case at the caller side. I will make that change.

[Joe Thomas, 2012/12/30 07:09:39]

We dont need a pointer to be returned. I will make use of base::LazyInstance and
return a reference here.

[Yoyo Zhou, 2013/01/03 22:36:03]

I'm not sure I understand how to use LazyInstance here. Can you explain what you
mean?

[Joe Thomas, 2013/01/04 23:36:11]

I was referring to creating a Lazy instance like below

struct EmptyURLOverrideMap {
  URLOverrideMap url_overrides;
};

static base::LazyInstance<EmptyURLOverrideMap> g_empty_overrides =
LAZY_INSTANCE_INITIALIZER;

and return g_empty_overrides.Get().url_overrides.

But since you mentioned that the above approach is not desirable in
https://chromiumcodereview.appspot.com/11741014/, I am returning a pointer here.

[Yoyo Zhou, 2013/01/05 00:46:11]

Ah, I have since commented on the other CL that I didn't object to the
LazyInstance but to the extra struct. You should be able to just have a
LazyInstance<URLOverrideMap>, and that would be fine.

[Joe Thomas, 2013/01/05 02:33:45]

Done.

+};
+
+// Parses the "chrome_url_overrides" manifest key.
+class URLOverridesHandler : public ManifestHandler {
+ public:
+  URLOverridesHandler();
+  virtual ~URLOverridesHandler();
+
+  virtual bool Parse(const base::Value* value,
+                     Extension* extension,
+                     string16* error) OVERRIDE;
+};
+
+}  // namespace extensions
+
+#endif  // CHROME_COMMON_EXTENSIONS_API_URL_OVERRIDES_URL_OVERRIDES_HANDLER_H_