ChromeLabs: Adding Uma histograms to track labs usage

Bug: 1145666
Change-Id: I7ba3301d7c5216d358953bb3223dee9992f139c1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2580340
Commit-Queue: Elaine Chien <elainechien@chromium.org>
Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Reviewed-by: Thomas Lukaszewicz <tluk@chromium.org>
Reviewed-by: Dana Fried <dfried@chromium.org>
Cr-Commit-Position: refs/heads/master@{#835900}

chrome/browser/ui/views/toolbar/chrome_labs_bubble_view.cc

@@ -4,8 +4,10 @@
 
 #include "chrome/browser/ui/views/toolbar/chrome_labs_bubble_view.h"
 #include "base/bind.h"
+#include "base/metrics/histogram_functions.h"
 #include "chrome/browser/about_flags.h"
 #include "chrome/browser/browser_process.h"
+#include "chrome/browser/flag_descriptions.h"
 #include "chrome/browser/lifetime/application_lifetime.h"
 #include "chrome/browser/ui/webui/flags/flags_ui.h"
 #include "chrome/grit/generated_resources.h"
@@ -19,6 +21,49 @@
 
 namespace {
 
+// These values are persisted to logs. Entries should not be renumbered and
+// numeric values should never be reused.
+enum class ChromeLabsSelectedLab {
+  kUnspecifiedSelected = 0,
+  kReadLaterSelected = 1,
+  kTabSearchSelected = 2,
+  kMaxValue = kTabSearchSelected,
+};
+
+void EmitToHistogram(const base::string16& selected_lab_state,
+                     const std::string& internal_name) {
+  const auto get_histogram_name = [](const base::string16& selected_lab_state) {
+    if (selected_lab_state == base::ASCIIToUTF16(base::StringPiece(
+                                  flags_ui::kGenericExperimentChoiceDefault))) {
+      return "Toolbar.ChromeLabs.DefaultLabAction";
+    } else if (selected_lab_state ==
+               base::ASCIIToUTF16(base::StringPiece(
+                   flags_ui::kGenericExperimentChoiceEnabled))) {
+      return "Toolbar.ChromeLabs.EnableLabAction";
+    } else if (selected_lab_state ==
+               base::ASCIIToUTF16(base::StringPiece(
+                   flags_ui::kGenericExperimentChoiceDisabled))) {
+      return "Toolbar.ChromeLabs.DisableLabAction";
+    } else {
+      return "";
+    }
+  };
+
+  const auto get_enum = [](const std::string& internal_name) {
+    if (internal_name == flag_descriptions::kReadLaterFlagId) {
+      return ChromeLabsSelectedLab::kReadLaterSelected;
+    } else if (internal_name == flag_descriptions::kEnableTabSearchFlagId) {
+      return ChromeLabsSelectedLab::kTabSearchSelected;
+    } else {
+      return ChromeLabsSelectedLab::kUnspecifiedSelected;
+    }
+  };
+
+  const std::string histogram_name = get_histogram_name(selected_lab_state);
+  if (!histogram_name.empty())
+    base::UmaHistogramEnumeration(histogram_name, get_enum(internal_name));
+}
+
 ChromeLabsBubbleView* g_chrome_labs_bubble = nullptr;
 
 class ChromeLabsFooter : public views::View {
@@ -130,6 +175,9 @@ std::unique_ptr<ChromeLabsItemView> ChromeLabsBubbleView::CreateLabItem(
         bubble_view->flags_storage_.get(),
         internal_name + "@" + base::NumberToString(selected_index), true);
     bubble_view->ShowRelaunchPrompt();
+    EmitToHistogram(
+        item_view->GetFeatureEntry()->DescriptionForOption(selected_index),
+        internal_name);
   };
 
   std::unique_ptr<ChromeLabsItemView> item_view =

tools/metrics/histograms/enums.xml

@@ -9806,6 +9806,12 @@ histogram as enum -->
   <int value="2" label="Startup"/>
 </enum>
 
+<enum name="ChromeLabsSelectedLab">
+  <int value="0" label="User selected an unspecified lab"/>
+  <int value="1" label="User selected the Read Later lab"/>
+  <int value="2" label="User selected the Tab Search lab"/>
+</enum>
+
 <enum name="ChromeMLServiceDecisionTreePredictionResult">
   <int value="0" label="Unknown"/>
   <int value="1" label="True"/>

tools/metrics/histograms/histograms_xml/others/histograms.xml

@@ -16004,6 +16004,25 @@ should be kept until we use this API.  -->
   <summary>Number of retries until the final response was recorded.</summary>
 </histogram>
 
+<histogram name="Toolbar.ChromeLabs.{State}LabAction"
+    enum="ChromeLabsSelectedLab" expires_after="M96">
+  <owner>elainechien@chromium.org</owner>
+  <owner>robliao@chromium.org</owner>
+  <summary>
+    Chrome Labs features user-facing experiments through a button in the
+    toolbar.
+
+    This metric tracks which experiment (also called lab in the context of
+    Chrome Labs) a user selects {State} for. This histogram is emitted to when
+    {State} is selected in the combobox of the ChromeLabs dialog.
+  </summary>
+  <token key="State">
+    <variant name="Default" summary="Default state selected for lab"/>
+    <variant name="Disable" summary="Disabled state selected for lab"/>
+    <variant name="Enable" summary="Enabled state selected for lab"/>
+  </token>
+</histogram>
+
 <histogram name="Toolbar.Menu.NewIncognitoTabPresentationDuration" units="ms"
     expires_after="M85">
   <owner>peterlaurens@chromium.org</owner>