Suggest about:blank autocompletion from BuiltinProvider.

chrome/browser/autocomplete/builtin_provider.cc

 // 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.
 
 #include "chrome/browser/autocomplete/builtin_provider.h"
 
 #include <algorithm>
 
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 51 matching lines @@
 }
 
 void BuiltinProvider::Start(const AutocompleteInput& input,
                             bool minimal_changes) {
   matches_.clear();
   if ((input.type() == AutocompleteInput::INVALID) ||
       (input.type() == AutocompleteInput::FORCED_QUERY) ||
       (input.type() == AutocompleteInput::QUERY))
     return;
 
+  const size_t kAboutSchemeLength = strlen(content::kAboutScheme);
   const base::string16 kAbout = base::ASCIIToUTF16(content::kAboutScheme) +
       base::ASCIIToUTF16(content::kStandardSchemeSeparator);
   const base::string16 kChrome = base::ASCIIToUTF16(content::kChromeUIScheme) +
       base::ASCIIToUTF16(content::kStandardSchemeSeparator);
 
   const int kUrl = ACMatchClassification::URL;
   const int kMatch = kUrl | ACMatchClassification::MATCH;
 
   base::string16 text = input.text();
   bool starting_chrome = StartsWith(kChrome, text, false);
   if (starting_chrome || StartsWith(kAbout, text, false)) {
     ACMatchClassifications styles;
     // Highlight the input portion matching "chrome://"; or if the user has
     // input "about:" (with optional slashes), highlight the whole "chrome://".
-    const size_t kAboutSchemeLength = strlen(content::kAboutScheme);
     bool highlight = starting_chrome || text.length() > kAboutSchemeLength;
     styles.push_back(ACMatchClassification(0, highlight ? kMatch : kUrl));
     size_t offset = starting_chrome ? text.length() : kChrome.length();
     if (highlight)
       styles.push_back(ACMatchClassification(offset, kUrl));
     // Include some common builtin chrome URLs as the user types the scheme.
     AddMatch(base::ASCIIToUTF16(chrome::kChromeUIChromeURLsURL),
              base::string16(), styles);
 #if !defined(OS_ANDROID)
     AddMatch(base::ASCIIToUTF16(chrome::kChromeUISettingsURL),
              base::string16(), styles);
 #endif
     AddMatch(base::ASCIIToUTF16(chrome::kChromeUIVersionURL),
              base::string16(), styles);
   } else {
     // Match input about: or chrome: URL input against builtin chrome URLs.
     GURL url = URLFixerUpper::FixupURL(base::UTF16ToUTF8(text), std::string());
     // BuiltinProvider doesn't know how to suggest valid ?query or #fragment
     // 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.
+      // This match does not allow any trailing path or slash in the input.

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

This comment restates the test.  I want to know why this test exists, because
the other builtin provider suggestions allow a trailing slash.

[msw, 2014/05/30 18:31:09]

Done.

+      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) &&
+          !EndsWith(text, base::ASCIIToUTF16("/"), false)) {
+        ACMatchClassifications styles;
+        styles.push_back(ACMatchClassification(0, kMatch));
+        base::string16 match = base::ASCIIToUTF16(content::kAboutBlankURL);
+        // Measure the length of the matching host after the "about:" scheme.
+        const size_t corrected_length = kAboutSchemeLength + 1 + host.length();
+        if (blank_host.length() > host.length())
+          styles.push_back(ACMatchClassification(corrected_length, kUrl));
+        AddMatch(match, match.substr(corrected_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(),
                        &host_and_path);
       size_t match_length = kChrome.length() + host_and_path.length();
       for (Builtins::const_iterator i(builtins_.begin());
           (i != builtins_.end()) && (matches_.size() < kMaxMatches); ++i) {
         if (StartsWith(*i, host_and_path, false)) {
           ACMatchClassifications styles;
           // Highlight the "chrome://" scheme, even for input "about:foo".
@@ skipping 26 matching lines @@
                                const ACMatchClassifications& styles) {
   AutocompleteMatch match(this, kRelevance, false,
                           AutocompleteMatchType::NAVSUGGEST);
   match.fill_into_edit = match_string;
   match.inline_autocompletion = inline_completion;
   match.destination_url = GURL(match_string);
   match.contents = match_string;
   match.contents_class = styles;
   matches_.push_back(match);
 }