Docserver: Enable GitHub content providers.

chrome/common/extensions/docs/templates/json/content_providers.json

Index: chrome/common/extensions/docs/templates/json/content_providers.json
diff --git a/chrome/common/extensions/docs/templates/json/content_providers.json b/chrome/common/extensions/docs/templates/json/content_providers.json
index 2e6599e304571f870f103a9a63e4164d048aab78..90c01182ba1b1ebc4cef19bc63bdc6c0cc93ab8c 100644
--- a/chrome/common/extensions/docs/templates/json/content_providers.json
+++ b/chrome/common/extensions/docs/templates/json/content_providers.json
@@ -9,11 +9,15 @@
 //  * An arbitrary identifier key e.g. "cr-extensions-examples".
 //  * What URL the rule should be invoked with, given by "serveFrom", e.g.
 //    "extensions/examples".
-//  * An object describing where the content originates; currently the only
-//    supported location is "chromium" with a key "dir" specifying which
-//    chromium directory to look in, e.g. "extensions/samples".
+//  * An object describing where the content originates, either "chromium"
+//    or "github".
+//  * "chromium" must provide a "dir" value specifying which chromium directory
+//     to look in, e.g. "extensions/samples".
+//  * "github" must provide "owner" and "repo" values specifying the owner of
+//    the GitHub repository, and the repository name, e.g. "GoogleChrome" and
+//    "chrome-app-samples" respectively.
 //
-// In this example, when the user navigates to
+// In the chromium example, when the user navigates to
 //
 //    developer.chrome.com/extensions/examples/some/sample/path
 //