Add metrics for schemes of content setting exceptions

components/content_settings/core/common/content_settings_pattern.cc

Index: components/content_settings/core/common/content_settings_pattern.cc
diff --git a/components/content_settings/core/common/content_settings_pattern.cc b/components/content_settings/core/common/content_settings_pattern.cc
index aa895948153c07fa1536be3d9346c80c9a2462c3..b9dbe6af393593cf856c784ea3ec645eb9d2cdc3 100644
--- a/components/content_settings/core/common/content_settings_pattern.cc
+++ b/components/content_settings/core/common/content_settings_pattern.cc
@@ -21,6 +21,15 @@ namespace {
 // The component supports only one scheme for simplicity.
 const char* non_port_non_domain_wildcard_scheme = NULL;
 
+const char* const kSchemeNames[] = {
+  "wildcard",
+  url::kHttpScheme,
+  url::kHttpsScheme,
+  url::kFileScheme,
+  "chrome-extension",
+  "other",
+};
+
 std::string GetDefaultPort(const std::string& scheme) {
   if (scheme == url::kHttpScheme)
     return "80";
@@ -590,6 +599,18 @@ std::string ContentSettingsPattern::ToString() const {
     return std::string();
 }
 
+ContentSettingsPattern::SchemeType ContentSettingsPattern::GetScheme() const {
+  if (parts_.is_scheme_wildcard)
+    return SCHEME_WILDCARD;
+
+  for (int i = 1; i < SCHEME_MAX - 1; ++i) {

[msramek, 2016/08/09 10:47:43]

We're iterating over kSchemeNames, so I would specify arraysize(kSchemeNames) as
the top bound. There currently isn't any coupling between kSchemeNames and
SCHEME_MAX, i.e. it can't be easily verified that this loop won't go out of
bounds.

Please also introduce such a coupling by adding
static_assert(arraysize(kSchemeNames) == SCHEME_MAX - 1)

[lshang, 2016/08/10 04:32:35]

Done. Good advice!

+    if (parts_.scheme == kSchemeNames[i]) {

[msramek, 2016/08/09 10:47:43]

nit: No braces needed for a one-line for() :)

[lshang, 2016/08/10 04:32:35]

Done.

+      return static_cast<SchemeType>(i);
+    }
+  }
+  return SCHEME_OTHER;
+}
+
 ContentSettingsPattern::Relation ContentSettingsPattern::Compare(
     const ContentSettingsPattern& other) const {
   // Two invalid patterns are identical in the way they behave. They don't match