List relevant IDs from Finch in snippets-internals

chrome/browser/ui/webui/snippets_internals_message_handler.cc

Index: chrome/browser/ui/webui/snippets_internals_message_handler.cc
diff --git a/chrome/browser/ui/webui/snippets_internals_message_handler.cc b/chrome/browser/ui/webui/snippets_internals_message_handler.cc
index 9b7798098caa38115c50019ad18ed5fc5be22f83..8f889cba5bb3965212624ec488124c7d744c4baf 100644
--- a/chrome/browser/ui/webui/snippets_internals_message_handler.cc
+++ b/chrome/browser/ui/webui/snippets_internals_message_handler.cc
@@ -16,9 +16,11 @@
 #include "base/i18n/time_formatting.h"
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
+#include "base/metrics/field_trial.h"
 #include "base/optional.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_split.h"
+#include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/values.h"
@@ -35,6 +37,7 @@
 #include "components/ntp_snippets/switches.h"
 #include "components/offline_pages/core/offline_page_feature.h"
 #include "components/prefs/pref_service.h"
+#include "components/variations/variations_associated_data.h"
 #include "content/public/browser/web_ui.h"
 
 using ntp_snippets::ContentSuggestion;
@@ -119,6 +122,31 @@ std::string GetCategoryStatusName(CategoryStatus status) {
   return std::string();
 }
 
+std::set<variations::VariationID> SnippetsExperiments() {
+  std::set<variations::VariationID> result;
+  for (const base::Feature* const* feature = ntp_snippets::kAllFeatures;
+       *feature; ++feature) {
+    base::FieldTrial* trial = base::FeatureList::GetFieldTrial(**feature);
+    if (!trial) {
+      continue;
+    }
+    if (trial->GetGroupNameWithoutActivation().empty()) {
+      continue;
+    }
+    for (variations::IDCollectionKey key :
+         {variations::GOOGLE_WEB_PROPERTIES,
+          variations::GOOGLE_WEB_PROPERTIES_SIGNED_IN,
+          variations::GOOGLE_WEB_PROPERTIES_TRIGGER}) {
+      const variations::VariationID id = variations::GetGoogleVariationID(
+          key, trial->trial_name(), trial->group_name());

[jkrcal, 2017/04/19 11:15:43]

Just want to double check: The fact that the group name is not empty implies
that the group is already activated and we can thus simply call
trial->group_name()?

[sfiera, 2017/04/19 11:40:18]

Yes, from my reading of the code, a non-empty group name implies the group is
already active.

I'm not sure if the empty string is a valid group name; if it is, then we would
miss experiment IDs from such a group. But I don't think we'll do that anyway.

[jkrcal, 2017/04/19 11:45:17]

Acknowledged.

+      if (id != variations::EMPTY_ID) {
+        result.insert(id);
+      }
+    }
+  }
+  return result;
+}
+
 }  // namespace
 
 SnippetsInternalsMessageHandler::SnippetsInternalsMessageHandler(
@@ -357,6 +385,13 @@ void SnippetsInternalsMessageHandler::SendAllContent() {
         base::Value(fetcher->last_json()));
   }
 
+  std::set<variations::VariationID> ids = SnippetsExperiments();
+  std::vector<std::string> string_ids;
+  for (auto id : ids) {
+    string_ids.push_back(base::IntToString(id));
+  }
+  SendString("experiment-ids", base::JoinString(string_ids, ", "));
+
   SendContentSuggestions();
 }