[Feed] Record metric for time until draw upper UI of NTP.

Bug: 889106
Change-Id: I7c5fa213d3ca323b495d1e785605e9e1f1b6f986
Reviewed-on: https://chromium-review.googlesource.com/c/1385482Reviewed-by: Steven Holte <holte@chromium.org>
Reviewed-by: Theresa <twellington@chromium.org>
Commit-Queue: Sky Malice <skym@chromium.org>
Cr-Commit-Position: refs/heads/master@{#619816}

chrome/android/feed/core/java/src/org/chromium/chrome/browser/feed/FeedNewTabPage.java

@@ -238,7 +238,7 @@ public class FeedNewTabPage extends NewTabPage {
         mNewTabPageLayout.initialize(mNewTabPageManager, mTab, mTileGroupDelegate,
                 mSearchProviderHasLogo,
                 TemplateUrlService.getInstance().isDefaultSearchEngineGoogle(), mMediator,
-                mContextMenuManager, mUiConfig);
+                mContextMenuManager, mUiConfig, mConstructedTimeNs);
     }
 
     @Override

chrome/android/java/src/org/chromium/chrome/browser/ntp/NewTabPage.java

@@ -101,7 +101,7 @@ public class NewTabPage
     private LocationBarVoiceRecognitionHandler mVoiceRecognitionHandler;
 
     // The timestamp at which the constructor was called.
-    private final long mConstructedTimeNs;
+    protected final long mConstructedTimeNs;
 
     // The timestamp at which this NTP was last shown to the user.
     private long mLastShownTimeNs;
@@ -360,7 +360,7 @@ public class NewTabPage
         mNewTabPageView.initialize(mNewTabPageManager, mTab, mTileGroupDelegate,
                 mSearchProviderHasLogo,
                 TemplateUrlService.getInstance().isDefaultSearchEngineGoogle(),
-                getScrollPositionFromNavigationEntry());
+                getScrollPositionFromNavigationEntry(), mConstructedTimeNs);
     }
 
     /**

chrome/android/java/src/org/chromium/chrome/browser/ntp/NewTabPageLayout.java

@@ -20,12 +20,15 @@ import android.view.MotionEvent;
 import android.view.View;
 import android.view.ViewGroup;
 import android.view.ViewStub;
+import android.view.ViewTreeObserver;
 import android.widget.ImageView;
 import android.widget.LinearLayout;
 import android.widget.TextView;
 
+import org.chromium.base.Log;
 import org.chromium.base.TraceEvent;
 import org.chromium.base.VisibleForTesting;
+import org.chromium.base.metrics.RecordHistogram;
 import org.chromium.chrome.R;
 import org.chromium.chrome.browser.compositor.layouts.EmptyOverviewModeObserver;
 import org.chromium.chrome.browser.compositor.layouts.LayoutManager;
@@ -64,6 +67,8 @@ import org.chromium.components.feature_engagement.Tracker;
 import org.chromium.ui.base.DeviceFormFactor;
 import org.chromium.ui.widget.ViewRectProvider;
 
+import java.util.concurrent.TimeUnit;
+
 /**
  * Layout for the new tab page. This positions the page elements in the correct vertical positions.
  * There are no separate phone and tablet UIs; this layout adapts based on the available space.
@@ -215,11 +220,12 @@ public class NewTabPageLayout extends LinearLayout implements TileGroup.Observer
      * @param scrollDelegate The delegate used to obtain information about scroll state.
      * @param contextMenuManager The manager for long-press context menus.
      * @param uiConfig UiConfig that provides display information about this view.
+     * @param constructedTimeNs The timestamp at which the new tab page's construction started.
      */
     public void initialize(NewTabPageManager manager, Tab tab, TileGroup.Delegate tileGroupDelegate,
             boolean searchProviderHasLogo, boolean searchProviderIsGoogle,
-            ScrollDelegate scrollDelegate, ContextMenuManager contextMenuManager,
-            UiConfig uiConfig) {
+            ScrollDelegate scrollDelegate, ContextMenuManager contextMenuManager, UiConfig uiConfig,
+            long constructedTimeNs) {
         TraceEvent.begin(TAG + ".initialize()");
         mScrollDelegate = scrollDelegate;
         mTab = tab;
@@ -293,6 +299,22 @@ public class NewTabPageLayout extends LinearLayout implements TileGroup.Observer
             }
         }
 
+        // Use preDraw instead of draw because api level 25 and earlier doesn't seem to call the
+        // onDraw listener. Also, the onDraw version cannot be removed inside of the notification,
+        // which complicates this.
+        getViewTreeObserver().addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() {
+            @Override
+            public boolean onPreDraw() {
+                Log.e(TAG, "SKYM onPreDraw()");
+                long timeToFirstDrawMs =
+                        TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - constructedTimeNs);
+                RecordHistogram.recordTimesHistogram(
+                        "NewTabPage.TimeToFirstDraw", timeToFirstDrawMs, TimeUnit.MILLISECONDS);
+                getViewTreeObserver().removeOnPreDrawListener(this);
+                return true;
+            }
+        });
+
         manager.addDestructionObserver(NewTabPageLayout.this::onDestroy);
 
         mInitialized = true;

chrome/android/java/src/org/chromium/chrome/browser/ntp/NewTabPageView.java

@@ -106,9 +106,11 @@ public class NewTabPageView extends FrameLayout {
      * @param searchProviderHasLogo Whether the search provider has a logo.
      * @param searchProviderIsGoogle Whether the search provider is Google.
      * @param scrollPosition The adapter scroll position to initialize to.
+     * @param constructedTimeNs The timestamp at which the new tab page's construction started.
      */
     public void initialize(NewTabPageManager manager, Tab tab, TileGroup.Delegate tileGroupDelegate,
-            boolean searchProviderHasLogo, boolean searchProviderIsGoogle, int scrollPosition) {
+            boolean searchProviderHasLogo, boolean searchProviderIsGoogle, int scrollPosition,
+            long constructedTimeNs) {
         TraceEvent.begin(TAG + ".initialize()");
         mTab = tab;
         mManager = manager;
@@ -125,7 +127,8 @@ public class NewTabPageView extends FrameLayout {
         mTab.getWindowAndroid().addContextMenuCloseListener(mContextMenuManager);
 
         mNewTabPageLayout.initialize(manager, tab, tileGroupDelegate, searchProviderHasLogo,
-                searchProviderIsGoogle, mRecyclerView, mContextMenuManager, mUiConfig);
+                searchProviderIsGoogle, mRecyclerView, mContextMenuManager, mUiConfig,
+                constructedTimeNs);
 
         mSnapScrollHelper = new SnapScrollHelper(mManager, mNewTabPageLayout);
         mSnapScrollHelper.setView(mRecyclerView);

tools/metrics/histograms/histograms.xml

@@ -69632,6 +69632,18 @@ uploading your change for review.
   </summary>
 </histogram>
 
+<histogram name="NewTabPage.TimeToFirstDraw" units="ms">
+  <owner>skym@chromium.org</owner>
+  <owner>twellington@chromium.org</owner>
+  <summary>
+    The time from when a new tab page is created until the first pre-draw call
+    on the main UI containing the search provider logo (if available), fake
+    search box, most visited tiles, etc. More specifically, this is the time
+    between NewTabPage's constructor and the first pre-draw pass on
+    NewTabPageLayout.
+  </summary>
+</histogram>
+
 <histogram name="NewTabPage.URLState" enum="NewTabURLState">
   <owner>treib@chromium.org</owner>
   <summary>