Suggest about:blank autocompletion from BuiltinProvider.

chrome/browser/autocomplete/builtin_provider.cc

Index: chrome/browser/autocomplete/builtin_provider.cc
diff --git a/chrome/browser/autocomplete/builtin_provider.cc b/chrome/browser/autocomplete/builtin_provider.cc
index 5b35c75fa0317aa646997e622f0d0e11c2f752a2..faf8769c93d5dd0cb8059aea002c2e3222d091fc 100644
--- a/chrome/browser/autocomplete/builtin_provider.cc
+++ b/chrome/browser/autocomplete/builtin_provider.cc
@@ -105,6 +105,21 @@ void BuiltinProvider::Start(const AutocompleteInput& input,
     // extensions to chrome: URLs.
     if (url.SchemeIs(content::kChromeUIScheme) && url.has_host() &&
         !url.has_query() && !url.has_ref()) {
+      // Suggest about:blank for substrings, taking URL fixup into account.

[Mark P, 2014/05/29 23:48:05]

Note that this was of doing it will put about:blank before any other
BuiltinProvider inputs that match the input.  i.e., if there were an  about:bee,
the matches would no longer be alphabetic as they were before.
I don't think this is an issue now.  Regardless, consider whether it's worth a
comment or a minor code change to leave things alphabetical.

[msw, 2014/05/30 00:29:49]

It might be considered alphabetical if you're comparing "about:blank" to
"chrome://blob-internals" and "chrome://bookmarks". I don't think it's really
worth a code comment.

[Mark P, 2014/05/30 18:16:41]

Okay.

+      const base::string16 blank_host = base::ASCIIToUTF16("blank");
+      const base::string16 host = base::UTF8ToUTF16(url.host());
+      if (StartsWith(text, base::ASCIIToUTF16(content::kAboutScheme), false) &&
+          StartsWith(blank_host, host, false) && url.path().length() <= 1 &&

[Mark P, 2014/05/29 23:48:05]

nit: parens around binary operator <=

[msw, 2014/05/30 00:29:49]

Done.

+          !EndsWith(text, base::ASCIIToUTF16("/"), false)) {

[Mark P, 2014/05/29 23:48:05]

please comment on the need for this final EndsWith clause.

[msw, 2014/05/30 00:29:49]

Done.

+        ACMatchClassifications styles;
+        styles.push_back(ACMatchClassification(0, kMatch));
+        base::string16 match = base::ASCIIToUTF16(content::kAboutBlankURL);
+        const size_t corrected_input_length = 6 + host.length();

[Mark P, 2014/05/29 23:48:05]

comment on the "6"
(and if it's 6 because this is the length of "about:" then why don't you
actually do length of kAboutScheme + ":"?)

[msw, 2014/05/30 00:29:49]

Done (used kAboutSchemeLength + 1) and added a comment.

+        if (blank_host.length() > host.length())
+          styles.push_back(ACMatchClassification(corrected_input_length, kUrl));
+        AddMatch(match, match.substr(corrected_input_length), styles);
+      }
+
       // Include the path for sub-pages (e.g. "chrome://settings/browser").
       base::string16 host_and_path = base::UTF8ToUTF16(url.host() + url.path());
       base::TrimString(host_and_path, base::ASCIIToUTF16("/").c_str(),