Added utility functions related to working with "facets".

components/password_manager/core/browser/affiliation_utils.cc

+// Copyright 2014 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 "components/password_manager/core/browser/affiliation_utils.h"
+
+#include "base/strings/string_util.h"
+#include "url/gurl.h"
+#include "url/third_party/mozilla/url_parse.h"
+
+namespace password_manager {
+
+const char kAndroidAppScheme[] = "android";
+
+bool IsValidFacetURI(const std::string& uri) {
+  return IsValidWebFacetURI(uri) || IsValidAndroidFacetURI(uri);
+}
+
+bool IsValidWebFacetURI(const std::string& uri) {
+  url::Parsed url_parsed;
+  url::ParseStandardURL(uri.c_str(), uri.size(), &url_parsed);

[Mike West, 2014/12/02 16:33:06]

Why parse this manually? Wouldn't it be easier to pass it to GURL, let GURL do
the work, and then test 'is_valid()'? Are there any cases in which |uri| would
be valid according to this method, but not accepted by GURL?

[engedy, 2014/12/02 19:24:55]

Using the GURL constructor is doable, but rather heavy-weight, as it will not
only parse the URL, but also canonicalize it. 

I would be fine with using GURL. Note that either, the rest of the function
(i.e. checking existence and non-existence of components) would need to be kept.

+  return url_parsed.scheme.is_nonempty() &&
+         LowerCaseEqualsASCII(&uri[url_parsed.scheme.begin],
+                              &uri[url_parsed.scheme.end()],
+                              url::kHttpsScheme) &&
+         !url_parsed.username.is_valid() && !url_parsed.password.is_valid() &&
+         url_parsed.host.is_nonempty() && url_parsed.path.is_nonempty() &&
+         url_parsed.path.len == 1 && uri[url_parsed.path.begin] == '/' &&
+         !url_parsed.query.is_valid() && !url_parsed.ref.is_valid();
+}
+
+bool IsValidAndroidFacetURI(const std::string& uri) {
+  // Treat URIs with the "android" scheme as standard URLs, so the APK hash will
+  // be treated as a username.
+  url::Parsed url_parsed;
+  url::ParseStandardURL(uri.c_str(), uri.size(), &url_parsed);

[Mike West, 2014/12/02 16:33:06]

Ditto.

[engedy, 2014/12/02 19:24:55]

This is, actually, different, see my comment in the header. (TL;DR: GURL's
high-level parser freaks out when it sees the "android" scheme, and shoves
everything into the path component. Therefore, this is the only solution. Should
I add more comments?)

+  return url_parsed.scheme.is_nonempty() &&
+         LowerCaseEqualsASCII(&uri[url_parsed.scheme.begin],
+                              &uri[url_parsed.scheme.end()],
+                              kAndroidAppScheme) &&
+         url_parsed.username.is_nonempty() && !url_parsed.password.is_valid() &&
+         url_parsed.host.is_nonempty() && !url_parsed.port.is_valid() &&
+         url_parsed.path.is_nonempty() && url_parsed.path.len == 1 &&
+         uri[url_parsed.path.begin] == '/' && !url_parsed.query.is_valid() &&
+         !url_parsed.ref.is_valid();
+}
+
+bool AreEquivalenceClassesEqual(const AffiliatedFacets& a,
+                                const AffiliatedFacets& b) {
+  if (a.size() != b.size())
+    return false;
+
+  std::vector<std::string> a_sorted(a.begin(), a.end());
+  std::vector<std::string> b_sorted(b.begin(), b.end());
+  std::sort(a_sorted.begin(), a_sorted.end());

[Mike West, 2014/12/02 16:33:06]

Hrm. Where do you intend to call this equality method? Sorting each time seems
potentially expensive. Perhaps we could store the data sorted?

That said, we're probably working with very small data sets, so optimizing this
might not be worth the time. Up to you. :)

[engedy, 2014/12/02 19:24:55]

I am not too worried about this, as most equivalence classes will contain 2 or 3
URIs, and this will be seldom called. I have added a comment to the header to
warn the caller.

+  std::sort(b_sorted.begin(), b_sorted.end());
+  return std::equal(a_sorted.begin(), a_sorted.end(), b_sorted.begin());
+}
+
+}  // namespace password_manager