Add the about_page key to shared_module manifest

chrome/common/extensions/manifest_url_handler.h

Index: chrome/common/extensions/manifest_url_handler.h
diff --git a/chrome/common/extensions/manifest_url_handler.h b/chrome/common/extensions/manifest_url_handler.h
index 057589b3cff35ba3ebbdd82f2f5ac5a01c6fb57a..bf286cf3c5c91bb9baf7484db451aae05a0bf021 100644
--- a/chrome/common/extensions/manifest_url_handler.h
+++ b/chrome/common/extensions/manifest_url_handler.h
@@ -40,6 +40,9 @@ struct ManifestURL : public Extension::ManifestData {
   // Returns the Options Page for this extension.
   static const GURL& GetOptionsPage(const Extension* extension);
 
+  // Returns the About Page for this extension.
+  static const GURL& GetAboutPage(const Extension* extension);
+
   // Returns the webstore page URL for this extension.
   static const GURL GetDetailsURL(const Extension* extension);
 };
@@ -120,6 +123,23 @@ class OptionsPageHandler : public ManifestHandler {
   DISALLOW_COPY_AND_ASSIGN(OptionsPageHandler);
 };
 
+// Parses the "options_page" manifest key.
+class AboutPageHandler : public ManifestHandler {
+ public:
+  AboutPageHandler();
+  virtual ~AboutPageHandler();
+
+  virtual bool Parse(Extension* extension, base::string16* error) OVERRIDE;
+  virtual bool Validate(const Extension* extension,

[benwells, 2014/06/05 03:59:17]

Do you know what calls this? It is weird that it uses a string resource to
return errors. Normally developer errors aren't translated.

[sashab, 2014/06/10 05:44:13]

Not sure what calls it (there are a lot of callsites - it's a complex path), but
the comment says that it's specifically for validating files associated with the
manifest key exist:
https://code.google.com/p/chromium/codesearch#chromium/src/extensions/common/...

There's also a TODO on the method that says to change the error to
base::string16, so I'm guessing it's just a bool at the moment because it hasn't
been fixed yet:
// TODO(yoz): Change error to base::string16. See crbug.com/71980.

[Yoyo Zhou, 2014/06/10 11:16:18]

This is principally called from extensions::file_util::ValidateExtension. I
think it may produce user-visible strings if e.g. the extension gets corrupted
on disk.

+                        std::string* error,
+                        std::vector<InstallWarning>* warnings) const OVERRIDE;
+
+ private:
+  virtual const std::vector<std::string> Keys() const OVERRIDE;
+
+  DISALLOW_COPY_AND_ASSIGN(AboutPageHandler);
+};
+
 // Parses the "chrome_url_overrides" manifest key.
 class URLOverridesHandler : public ManifestHandler {
  public: