[Instant Start] Track first draw time on UMA

Record Startup.Android.FirstDrawCompletedTime.{Instant,NoInstant}.

Bug: 1092931
Change-Id: I2d589ddc7f880cd7ccfc3c3fe45c46409896a035
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2355590Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Reviewed-by: Yaron Friedman <yfriedman@chromium.org>
Reviewed-by: Wei-Yin Chen (陳威尹) <wychen@chromium.org>
Commit-Queue: Xi Han <hanxi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#799728}

chrome/android/features/start_surface/internal/javatests/src/org/chromium/chrome/features/start_surface/StartSurfaceTest.java

@@ -79,6 +79,7 @@ import org.chromium.chrome.browser.feed.FeedSurfaceMediator;
 import org.chromium.chrome.browser.flags.CachedFeatureFlags;
 import org.chromium.chrome.browser.flags.ChromeFeatureList;
 import org.chromium.chrome.browser.flags.ChromeSwitches;
+import org.chromium.chrome.browser.init.AsyncInitializationActivity;
 import org.chromium.chrome.browser.ntp.NewTabPage;
 import org.chromium.chrome.browser.tasks.ReturnToChromeExperimentsUtil;
 import org.chromium.chrome.browser.tasks.SingleTabSwitcherMediator;
@@ -986,6 +987,11 @@ public class StartSurfaceTest {
                 CriteriaHelper.DEFAULT_POLLING_INTERVAL);
 
         boolean isInstantStart = TabUiFeatureUtilities.supportInstantStart(false);
+        Assert.assertEquals(1,
+                RecordHistogram.getHistogramTotalCountForTesting(
+                        StartSurfaceConfiguration.getHistogramName(
+                                AsyncInitializationActivity.FIRST_DRAW_COMPLETED_TIME_MS_UMA,
+                                isInstantStart)));
         int expectedRecordCount = mImmediateReturn ? 1 : 0;
         // Histograms should be only recorded when StartSurface is shown immediately after
         // launch.

chrome/android/java/src/org/chromium/chrome/browser/init/AsyncInitializationActivity.java

@@ -45,6 +45,7 @@ import org.chromium.chrome.browser.multiwindow.MultiWindowModeStateDispatcher;
 import org.chromium.chrome.browser.multiwindow.MultiWindowModeStateDispatcherImpl;
 import org.chromium.chrome.browser.profiles.Profile;
 import org.chromium.chrome.browser.tasks.tab_management.TabUiFeatureUtilities;
+import org.chromium.chrome.features.start_surface.StartSurfaceConfiguration;
 import org.chromium.ui.base.ActivityWindowAndroid;
 import org.chromium.ui.base.DeviceFormFactor;
 import org.chromium.ui.base.WindowAndroid;
@@ -60,6 +61,8 @@ import java.lang.reflect.Field;
  */
 public abstract class AsyncInitializationActivity extends ChromeBaseAppCompatActivity
         implements ChromeActivityNativeDelegate, BrowserParts, ModalDialogManagerHolder {
+    @VisibleForTesting
+    public static final String FIRST_DRAW_COMPLETED_TIME_MS_UMA = "FirstDrawCompletedTime";
     private static final String TAG = "AsyncInitActivity";
     protected final Handler mHandler;
 
@@ -74,9 +77,6 @@ public abstract class AsyncInitializationActivity extends ChromeBaseAppCompatAct
     /** Time at which onCreate is called. This is realtime, counted in ms since device boot. */
     private long mOnCreateTimestampMs;
 
-    /** Time at which onCreate is called. This is uptime, to be sent to native code. */
-    private long mOnCreateTimestampUptimeMs;
-
     private ActivityWindowAndroid mWindowAndroid;
     private final ObservableSupplierImpl<ModalDialogManager> mModalDialogManagerSupplier =
             new ObservableSupplierImpl<>();
@@ -216,6 +216,9 @@ public abstract class AsyncInitializationActivity extends ChromeBaseAppCompatAct
         assert firstDrawView != null;
         FirstDrawDetector.waitForFirstDraw(firstDrawView, () -> {
             mFirstDrawComplete = true;
+            StartSurfaceConfiguration.recordHistogram(FIRST_DRAW_COMPLETED_TIME_MS_UMA,
+                    SystemClock.elapsedRealtime() - getOnCreateTimestampMs(),
+                    TabUiFeatureUtilities.supportInstantStart(isTablet()));
             if (!mStartupDelayed) {
                 onFirstDrawComplete();
             }
@@ -332,7 +335,6 @@ public abstract class AsyncInitializationActivity extends ChromeBaseAppCompatAct
             super.onCreate(transformSavedInstanceStateForOnCreate(savedInstanceState));
         }
         mOnCreateTimestampMs = SystemClock.elapsedRealtime();
-        mOnCreateTimestampUptimeMs = SystemClock.uptimeMillis();
         mSavedInstanceState = savedInstanceState;
 
         mWindowAndroid = createWindowAndroid();
@@ -449,13 +451,6 @@ public abstract class AsyncInitializationActivity extends ChromeBaseAppCompatAct
         return intent;
     }
 
-    /**
-     * @return The elapsed real time for the activity creation in ms.
-     */
-    protected long getOnCreateTimestampUptimeMs() {
-        return mOnCreateTimestampUptimeMs;
-    }
-
     /**
      * @return The uptime for the activity creation in ms.
      */

tools/metrics/histograms/histograms.xml

@@ -171160,6 +171160,18 @@ should be kept until we use this API.  -->
   </summary>
 </histogram>
 
+<histogram base="true" name="Startup.Android.FirstDrawCompletedTime" units="ms"
+    expires_after="2021-06-10">
+<!-- Name completed by histogram_suffixes name="JavaStartMode" -->
+
+  <owner>hanxi@chromium.org</owner>
+  <owner>spdonghao@chromium.org</owner>
+  <owner>wychen@chromium.org</owner>
+  <summary>
+    Records the time duration from a cold start till the first draw completes.
+  </summary>
+</histogram>
+
 <histogram name="Startup.Android.GURLEnsureMainDexInitialized" units="ms"
     expires_after="2021-01-31">
   <owner>mthiesse@chromium.org</owner>
@@ -205877,6 +205889,7 @@ regressions. -->
   <suffix name="NoInstant" label=""/>
   <affected-histogram name="Startup.Android.FeedContentFirstLoadedTime"/>
   <affected-histogram name="Startup.Android.FeedStreamCreatedTime"/>
+  <affected-histogram name="Startup.Android.FirstDrawCompletedTime"/>
   <affected-histogram name="Startup.Android.SingleTabTitleAvailableTime"/>
 </histogram_suffixes>