Add a new entry to omnibox_event.proto to log specific type of contextual suggestions

components/omnibox/browser/omnibox_field_trial.cc

Index: components/omnibox/browser/omnibox_field_trial.cc
diff --git a/components/omnibox/browser/omnibox_field_trial.cc b/components/omnibox/browser/omnibox_field_trial.cc
index 378027ff0bc2748b7e25fac1086ed2b30034d053..b17929f111fdc7159e5fd28140e21ae2c18a209c 100644
--- a/components/omnibox/browser/omnibox_field_trial.cc
+++ b/components/omnibox/browser/omnibox_field_trial.cc
@@ -11,6 +11,7 @@
 #include "base/feature_list.h"
 #include "base/metrics/field_trial.h"
 #include "base/metrics/field_trial_params.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
@@ -797,3 +798,61 @@ std::string OmniboxFieldTrial::GetValueForRuleInContext(
   it = params.find(rule + ":*:*");
   return (it != params.end()) ? it->second : std::string();
 }
+
+namespace {
+
+static const char* kContextualZeroSuggests[] = {"" /*type is not set*/,
+                                                "cooccurrence_pages",

[Mark P, 2017/03/14 20:17:49]

If we keep the human-readable names (and maybe if not), we will need to check
with the search leads to confirm that they're comfortable with revealing the
components of the suggestion system.  (This is probably okay.  They have pushed
back on specific logging--more detailed than this--in the past, so it can't hurt
to check.)

[gcomanici, 2017/03/14 20:42:55]

Can you CC somebody that can do this? Or, should I instead do this in a separate
thread? Note I could alternatively make a change on the server side to provide
numerical ids instead of these names.

[Mark P, 2017/03/14 21:04:09]

I can help do this once we have a concrete proposal for what you want to log and
where.

[gcomanici, 2017/03/15 01:35:56]

SG

+                                                "hivemind_urls",
+                                                "local_store-maps",
+                                                "local_store-webpage",
+                                                "local_store-reservation",
+                                                "movie_reviews-review",
+                                                "movie_reviews-showtimes",
+                                                "on_the_news",
+                                                "popular_domains",
+                                                "similar_pages",
+                                                "top_entity_info",
+                                                "other"};
+}
+
+// static
+std::string OmniboxFieldTrial::ContextualZeroSuggest::ToString(
+    const Type& type) {
+  static_assert(
+      arraysize(kContextualZeroSuggests) == ContextualZeroSuggest::NUM_TYPES,
+      "kContextualZeroSuggests array must have NUM_TYPES elements");
+  return kContextualZeroSuggests[type];
+}
+
+// static
+OmniboxFieldTrial::ContextualZeroSuggest::Type
+OmniboxFieldTrial::ContextualZeroSuggest::FromString(const std::string& type) {
+  if (type.empty())
+    return NOT_SET;
+  for (int i = 0; i < NUM_TYPES; ++i) {
+    if (kContextualZeroSuggests[i] == type) {
+      return (Type)i;
+    }
+  }
+  return OTHER;
+}
+
+// static
+void OmniboxFieldTrial::ContextualZeroSuggest::RecordTypeAsProvided(
+    const std::string& type_as_string) {
+  const auto type = FromString(type_as_string);
+  if (type != NOT_SET)
+    UMA_HISTOGRAM_ENUMERATION(
+        "ZeroSuggest.ContextualSuggestType.SuggestionProvided", type,
+        NUM_TYPES);
+}
+
+// static
+void OmniboxFieldTrial::ContextualZeroSuggest::RecordTypeAsUsed(
+    const std::string& type_as_string) {
+  const auto type = FromString(type_as_string);
+  if (type != NOT_SET)
+    UMA_HISTOGRAM_ENUMERATION(
+        "ZeroSuggest.ContextualSuggestType.SuggestionUsed", type, NUM_TYPES);
+}