Do not sanitize about:blank/#foo & about:blank?foo

content/public/common/url_constants.h

Index: content/public/common/url_constants.h
diff --git a/content/public/common/url_constants.h b/content/public/common/url_constants.h
index 9e51257ae05789592564a531bd45706f5dfb164c..87e292fc0db01848ba81860a9231b9416420a712 100644
--- a/content/public/common/url_constants.h
+++ b/content/public/common/url_constants.h
@@ -27,6 +27,9 @@ CONTENT_EXPORT extern const char kExternalFileScheme[];
 // Hosts for about URLs.
 CONTENT_EXPORT extern const char kAboutSrcDocURL[];
 
+CONTENT_EXPORT extern const char kAboutBlankPath[];

[clamy, 2017/01/19 17:54:51]

Note: I've put all this in this file since it seemed to be the only file in
content/ with url constants, even though I'm not using it outside of content/.
If you have a suggestion for a better place to put it that'd be nice.

[Charlie Reis, 2017/01/19 22:36:35]

I was going to suggest content/common/content_constants_internal.h, but I wonder
if it's better to add an external use in this CL and just keep it public.  That
may help us understand this a bit more as well.

For example, from a quick glance I noticed WillHandleBrowserAboutURL in
chrome/browser/browser_about_handler.cc, which DCHECKs if the URL has an about:
scheme but isn't equal to kAboutBlankURL.  That pointed me to FixupURL in
components/url_formatter/url_fixer.cc, which rewrites any about: URLs to chrome:
URLs unless they're equal to kAboutBlankURL.  And indeed, we seem to have a bug
where you can't type about:blank/#foo into the omnibox!  (Firefox supports this;
Edge does not.)

This isn't high impact to users, but maybe it's worth correcting?  If so, maybe
your IsAboutBlankURL utility and these constants actually belong in
url/url_util.h and url/url_constants.h?  mkwst@ may have thoughts on this.

[clamy, 2017/01/20 12:51:53]

As per mkwst@ input, I've moved this to url/.

+CONTENT_EXPORT extern const char kAboutBlankWithHashPath[];
+
 CONTENT_EXPORT extern const char kChromeUIAccessibilityHost[];
 CONTENT_EXPORT extern const char kChromeUIAppCacheInternalsHost[];
 CONTENT_EXPORT extern const char kChromeUIBlobInternalsHost[];