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..d6246d21acd90cfbddd24f1a277443ba615d3642 100644
--- a/components/content_settings/core/common/content_settings_pattern.cc
+++ b/components/content_settings/core/common/content_settings_pattern.cc
@@ -21,6 +21,14 @@ namespace {
 // The component supports only one scheme for simplicity.
 const char* non_port_non_domain_wildcard_scheme = NULL;
 
+const char* const kSchemeNames[] = {
+  "unknown",

[msramek, 2016/08/08 17:33:12]

I would add kFileSystemScheme as well. It seems to be a mess to handle it, and
it's deprecated anyway as far as I know, so I wonder what the usage is.

[lshang, 2016/08/09 01:56:40]

I considered this scheme, but as you can see in the test, ContentSettingsPattern
seems don't store filesystem scheme(it's scheme is ""), so I regard it as
unknown before.

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

Acknowledged.

+  url::kHttpScheme,
+  url::kHttpsScheme,
+  url::kFileScheme,
+  "chrome-extension",
+};
+
 std::string GetDefaultPort(const std::string& scheme) {
   if (scheme == url::kHttpScheme)
     return "80";
@@ -590,6 +598,19 @@ std::string ContentSettingsPattern::ToString() const {
     return std::string();
 }
 
+ContentSettingsPattern::SchemeType ContentSettingsPattern::GetScheme() const {
+  if (parts_.is_scheme_wildcard)
+    return SCHEME_UNKNOWN;

[msramek, 2016/08/08 17:33:12]

I would leave UNKNOWN for something that is really UNKNOWN (line 604) and be
explicit here (line 603) that it's a WILDCARD.

[lshang, 2016/08/09 01:56:40]

Done. Good point!

+  SchemeType scheme = SCHEME_UNKNOWN;
+  for (int i = 1; i < SCHEME_MAX; ++i) {
+    if (parts_.scheme == kSchemeNames[i]) {
+      scheme = static_cast<SchemeType>(i);
+      break;
+    }
+  }
+  return scheme;

[msramek, 2016/08/08 17:33:12]

Optional style suggestion: Consider returning the found value directly from the
for-loop (line 607), and hardcoding UNKNOWN here (line 611).

[lshang, 2016/08/09 01:56:40]

Done. And I also changed UNKNOWN to OTHER, which I think is more clear when we
add WILDCARD as well.

+}
+
 ContentSettingsPattern::Relation ContentSettingsPattern::Compare(
     const ContentSettingsPattern& other) const {
   // Two invalid patterns are identical in the way they behave. They don't match