[Instant Start] Delay sign-in box to fade in together with Feed.

The sign-in box shows earlier than the Feed articles, and the Feed
placeholder looks strange during this period of time. This CL delays
the sign-in box and makes it fade in together with the Feed articles.

Bug: 1114190
Change-Id: Ifd353fe5bf318baaf61b7419e561b673a5852b87
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2314267
Commit-Queue: Hao Dong <spdonghao@chromium.org>
Reviewed-by: Carlos Knippschild <carlosk@chromium.org>
Reviewed-by: Wei-Yin Chen (陳威尹) <wychen@chromium.org>
Reviewed-by: Xi Han <hanxi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#796129}

chrome/android/features/start_surface/internal/java/src/org/chromium/chrome/features/start_surface/StartSurfaceMediator.java

@@ -150,14 +150,14 @@ class StartSurfaceMediator
     private boolean mExcludeMVTiles;
     private boolean mShowStackTabSwitcher;
     /**
-     * The value of {@link Pref.ARTICLES_LIST_VISIBLE} on Startup. Getting this value for recording
-     * the consistency of {@link ChromePreferenceKeys.FEED_ARTICLES_LIST_VISIBLE} with {@link
-     * Pref.ARTICLES_LIST_VISIBLE}.
+     * The value of {@link Pref#ARTICLES_LIST_VISIBLE} on Startup. Getting this value for recording
+     * the consistency of {@link ChromePreferenceKeys#FEED_ARTICLES_LIST_VISIBLE} with {@link
+     * Pref#ARTICLES_LIST_VISIBLE}.
      */
     private Boolean mFeedVisibilityPrefOnStartUp;
     /**
-     * The value of {@link ChromePreferenceKeys.FEED_ARTICLES_LIST_VISIBLE} on Startup. Getting this
-     * value for recording the consistency with {@link Pref.ARTICLES_LIST_VISIBLE}.
+     * The value of {@link ChromePreferenceKeys#FEED_ARTICLES_LIST_VISIBLE} on Startup. Getting this
+     * value for recording the consistency with {@link Pref#ARTICLES_LIST_VISIBLE}.
      */
     @Nullable
     private Boolean mFeedVisibilityInSharedPreferenceOnStartUp;

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

@@ -74,6 +74,7 @@ public class FeedSurfaceCoordinator implements FeedSurfaceProvider {
     private final View mNtpHeader;
     private final boolean mShowDarkBackground;
     private final boolean mIsPlaceholderShown;
+    private final boolean mIsPlaceholderShownInV1;
     private final boolean mV2Enabled;
     private final FeedSurfaceDelegate mDelegate;
     private final int mDefaultMargin;
@@ -221,6 +222,7 @@ public class FeedSurfaceCoordinator implements FeedSurfaceProvider {
         mIsPlaceholderShown = isPlaceholderShown;
         mV2Enabled = FeatureList.isInitialized()
                 && ChromeFeatureList.isEnabled(ChromeFeatureList.INTEREST_FEED_V2);
+        mIsPlaceholderShownInV1 = mIsPlaceholderShown && !mV2Enabled;
         mDelegate = delegate;
         mPageNavigationDelegate = pageNavigationDelegate;
         mBottomSheetController = bottomSheetController;
@@ -305,6 +307,11 @@ public class FeedSurfaceCoordinator implements FeedSurfaceProvider {
         return mStream;
     }
 
+    /** @return Whether the placeholder shows in V1. */
+    public boolean isPlaceholderShownInV1() {
+        return mIsPlaceholderShownInV1;
+    }
+
     /**
      * Create a {@link Stream} for this class.
      */
@@ -316,9 +323,7 @@ public class FeedSurfaceCoordinator implements FeedSurfaceProvider {
             mScrollViewResizer = null;
         }
 
-        boolean isPlaceholderShownInV1 = mIsPlaceholderShown && !mV2Enabled;
         mStreamCreatedTimeMs = SystemClock.elapsedRealtime();
-
         if (mV2Enabled) {
             mStream = new FeedStream(mActivity, mShowDarkBackground, mSnackbarManager,
                     mPageNavigationDelegate, mBottomSheetController);
@@ -333,14 +338,14 @@ public class FeedSurfaceCoordinator implements FeedSurfaceProvider {
                     FeedProcessScopeFactory.getFeedConsumptionObserver(),
                     FeedProcessScopeFactory.getFeedLoggingBridge(), mActivity, mProfile);
             mStream = FeedV1StreamCreator.createStream(mActivity, mImageLoader, actionApi,
-                    mUiConfig, mSnackbarManager, mShowDarkBackground, isPlaceholderShownInV1);
+                    mUiConfig, mSnackbarManager, mShowDarkBackground, mIsPlaceholderShownInV1);
         }
 
         mStreamLifecycleManager = mDelegate.createStreamLifecycleManager(mStream, mActivity);
 
         View view = mStream.getView();
         view.setBackgroundResource(R.color.default_bg_color);
-        if (isPlaceholderShownInV1) {
+        if (mIsPlaceholderShownInV1) {
             // Set recyclerView as transparent until first patch of articles are loaded. Before
             // that, the placeholder is shown.
             view.getBackground().setAlpha(0);
@@ -448,6 +453,11 @@ public class FeedSurfaceCoordinator implements FeedSurfaceProvider {
             mSigninPromoView = (PersonalizedSigninPromoView) inflater.inflate(
                     R.layout.personalized_signin_promo_view_modern_content_suggestions, mRootView,
                     false);
+            // If the placeholder is shown in V1, delay to show the sign-in view until the articles
+            // are shown.
+            if (mIsPlaceholderShownInV1) {
+                mSigninPromoView.setVisibility(View.INVISIBLE);
+            }
         }
         return mSigninPromoView;
     }

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

@@ -14,6 +14,7 @@ import android.widget.ScrollView;
 
 import androidx.annotation.Nullable;
 import androidx.annotation.VisibleForTesting;
+import androidx.recyclerview.widget.RecyclerView;
 
 import org.chromium.base.MemoryPressureListener;
 import org.chromium.base.memory.MemoryPressureCallback;
@@ -205,6 +206,9 @@ public class FeedSurfaceMediator
 
             @Override
             public void onAddFinished() {
+                // After first batch of articles are loaded, set recyclerView back to
+                // non-transparent.
+                stream.getView().getBackground().setAlpha(255);
                 if (mContentFirstAvailableTimeMs == 0) {
                     mContentFirstAvailableTimeMs = SystemClock.elapsedRealtime();
                     if (mHasPendingUmaRecording) {
@@ -214,6 +218,24 @@ public class FeedSurfaceMediator
                 }
                 mIsLoadingFeed = false;
             }
+
+            @Override
+            public void onAddStarting() {
+                if (!mCoordinator.isPlaceholderShownInV1()) {
+                    return;
+                }
+                // If the placeholder is shown, set sign-in box visible back.
+                RecyclerView recyclerView = (RecyclerView) stream.getView();
+                if (recyclerView != null) {
+                    View signInView = recyclerView.findViewById(R.id.signin_promo_view_container);
+                    if (signInView != null) {
+                        signInView.setAlpha(0f);
+                        signInView.setVisibility(View.VISIBLE);
+                        signInView.animate().alpha(1f).setDuration(
+                                recyclerView.getItemAnimator().getAddDuration());
+                    }
+                }
+            }
         };
         stream.addOnContentChangedListener(mStreamContentChangedListener);
 

chrome/android/feed/core/java/src/org/chromium/chrome/browser/feed/library/basicstream/internal/StreamItemAnimator.java

@@ -31,11 +31,15 @@ public class StreamItemAnimator extends DefaultItemAnimator {
     @Override
     public void onAddFinished(RecyclerView.ViewHolder item) {
         super.onAddFinished(item);
-        // After first patch of articles are loaded, set recyclerView back to non-transparent.
-        mParent.getBackground().setAlpha(255);
         mContentChangedListener.onAddFinished();
     }
 
+    @Override
+    public void onAddStarting(RecyclerView.ViewHolder item) {
+        super.onAddStarting(item);
+        mContentChangedListener.onAddStarting();
+    }
+
     @Override
     public void onAnimationFinished(RecyclerView.ViewHolder viewHolder) {
         super.onAnimationFinished(viewHolder);

chrome/android/feed/core/java/src/org/chromium/chrome/browser/feed/library/sharedstream/contentchanged/StreamContentChangedListener.java

@@ -35,4 +35,11 @@ public class StreamContentChangedListener implements ContentChangedListener {
             listener.onAddFinished();
         }
     }
+
+    @Override
+    public void onAddStarting() {
+        for (ContentChangedListener listener : mListeners) {
+            listener.onAddStarting();
+        }
+    }
 }

chrome/android/feed/core/java/src/org/chromium/chrome/browser/feed/shared/stream/Stream.java

@@ -153,6 +153,12 @@ public interface Stream {
          * {@link androidx.recyclerview.widget.SimpleItemAnimator#onAddFinished} event is received.
          */
         default void onAddFinished(){};
+
+        /**
+         * Called by Stream when an
+         * {@link androidx.recyclerview.widget.SimpleItemAnimator#onAddStarting} event is received.
+         */
+        default void onAddStarting(){};
     }
 
     /** Interface users can implement to be told about changes to scrolling in the Stream. */