Add histogram to measure the time taken to start watching

Adds a histogram that measure the time taken it took from
loading the page to when the user starts watching.

Change-Id: Ifbbcb5ca07c8554e7157ba1b07d3015fb801fe35
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2537777
Commit-Queue: Becca Hughes <beccahughes@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Weilun Shi <sweilun@chromium.org>
Reviewed-by: Ilya Sherman <isherman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#828901}

chrome/browser/media/kaleidoscope/kaleidoscope_data_provider_impl.cc

@@ -7,6 +7,7 @@
 #include <memory>
 
 #include "base/callback.h"
+#include "base/metrics/histogram_functions.h"
 #include "base/strings/string_util.h"
 #include "chrome/browser/media/history/media_history_keyed_service.h"
 #include "chrome/browser/media/history/media_history_keyed_service_factory.h"
@@ -313,6 +314,12 @@ void KaleidoscopeDataProviderImpl::SetSignedOutProviders(
       kaleidoscope::prefs::kKaleidoscopeSignedOutProviders, *providers_copy);
 }
 
+void KaleidoscopeDataProviderImpl::RecordTimeTakenToStartWatchHistogram(
+    base::TimeDelta time) {
+  base::UmaHistogramMediumTimes("Media.Kaleidoscope.TimeTakenToStartWatch",
+                                time);
+}
+
 void KaleidoscopeDataProviderImpl::OnGotCredentialsForCollections(
     const std::string& request,
     GetCollectionsCallback cb,

chrome/browser/media/kaleidoscope/kaleidoscope_data_provider_impl.h

@@ -68,6 +68,7 @@ class KaleidoscopeDataProviderImpl
   void GetSignedOutProviders(GetSignedOutProvidersCallback cb) override;
   void SetSignedOutProviders(
       const std::vector<std::string>& providers) override;
+  void RecordTimeTakenToStartWatchHistogram(base::TimeDelta time) override;
 
  private:
   media_history::MediaHistoryKeyedService* GetMediaHistoryService();

chrome/browser/media/kaleidoscope/mojom/kaleidoscope.mojom

@@ -106,6 +106,9 @@ interface KaleidoscopeDataProvider {
   // Stores a list of providers that were chosen by the user. Only used if the
   // user is signed out.
   SetSignedOutProviders(array<string> providers);
+
+  // Records a histogram of the time taken to start a watch action.
+  RecordTimeTakenToStartWatchHistogram(mojo_base.mojom.TimeDelta time);
 };
 
 enum GetCollectionsResult {

tools/metrics/histograms/histograms_xml/media/histograms.xml

@@ -2183,6 +2183,17 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
   </summary>
 </histogram>
 
+<histogram name="Media.Kaleidoscope.TimeTakenToStartWatch" units="ms"
+    expires_after="2021-08-19">
+  <owner>beccahughes@chromium.org</owner>
+  <owner>media-dev@chromium.org</owner>
+  <summary>
+    Recorded the first time in a Kaleidoscope session a user selects a watch
+    action in Kaleidoscope with the time taken from loading the page to the user
+    clicking on the watch action.
+  </summary>
+</histogram>
+
 <histogram base="true" name="Media.Learning.BinaryThreshold.Aggregate"
     enum="ConfusionMatrix" expires_after="2019-10-30">
 <!-- Name completed by histogram_suffixes