Bug 1786119 - Set current size to EdgeEffect when reinitializing Over…

…scrollEdgeEffect. r=geckoview-reviewers,owlish

When switching to previous tab, overscroll animation doesn't work since new
`EdgeEffect` doesn't have size. So we should set it from previous information.
If new size is available, `GeckoSession.onWindowBoundsChanged` will set new
size.

Also, this fix includes that `OverscrollEdgeEffect` doesn't use current
`GeckoSession` to draw edge effect. When switching to new `GeckoSession`,
we should set it to `OverscrollEdgeEffect`. `OverscrollEdgeEffect` is public
API, so I don't modify it for this.

Differential Revision: https://phabricator.services.mozilla.com/D155144

mobile/android/geckoview/src/main/java/org/mozilla/geckoview/GeckoSession.java

@@ -5255,7 +5255,7 @@ default void onScrollChanged(
     ThreadUtils.assertOnUiThread();
 
     if (mOverscroll == null) {
-      mOverscroll = new OverscrollEdgeEffect(this);
+      mOverscroll = new OverscrollEdgeEffect();
     }
     return mOverscroll;
   }

mobile/android/geckoview/src/main/java/org/mozilla/geckoview/GeckoView.java

@@ -448,6 +448,7 @@ private int defaultColor() {
     final GeckoSession session = mSession;
     mSession.releaseDisplay(mDisplay.release());
     mSession.getOverscrollEdgeEffect().setInvalidationCallback(null);
+    mSession.getOverscrollEdgeEffect().setSession(null);
     mSession.getCompositorController().setFirstPaintCallback(null);
 
     if (mSession.getAccessibility().getView() == this) {
@@ -525,6 +526,7 @@ public void setSession(@NonNull final GeckoSession session) {
 
     final Context context = getContext();
     session.getOverscrollEdgeEffect().setTheme(context);
+    session.getOverscrollEdgeEffect().setSession(session);
     session
         .getOverscrollEdgeEffect()
         .setInvalidationCallback(

mobile/android/geckoview/src/main/java/org/mozilla/geckoview/OverscrollEdgeEffect.java

@@ -31,14 +31,12 @@ public final class OverscrollEdgeEffect {
   // All four edges of the screen
   private final EdgeEffect[] mEdges = new EdgeEffect[4];
 
-  private final GeckoSession mSession;
+  private GeckoSession mSession;
   private Runnable mInvalidationCallback;
   private int mWidth;
   private int mHeight;
 
-  /* package */ OverscrollEdgeEffect(final GeckoSession session) {
-    mSession = session;
-  }
+  /* package */ OverscrollEdgeEffect() {}
 
   private static Field sPaintField;
 
@@ -61,11 +59,18 @@ public void setTheme(final @NonNull Context context) {
 
     for (int i = 0; i < mEdges.length; i++) {
       final EdgeEffect edgeEffect = new EdgeEffect(context);
+      if (mWidth != 0 || mHeight != 0) {
+        edgeEffect.setSize(mWidth, mHeight);
+      }
       setBlendMode(edgeEffect);
       mEdges[i] = edgeEffect;
     }
   }
 
+  /* package */ void setSession(final @Nullable GeckoSession session) {
+    mSession = session;
+  }
+
   /**
    * Set a Runnable that acts as a callback to invalidate the overscroll effect (for example, as a
    * response to user fling for example). The Runnbale should schedule a future call to {@link
@@ -154,6 +159,10 @@ private EdgeEffect getEdgeForAxisAndSide(final int axis, final float side) {
   public void draw(final @NonNull Canvas canvas) {
     ThreadUtils.assertOnUiThread();
 
+    if (mSession == null) {
+      return;
+    }
+
     final Rect pageRect = new Rect();
     mSession.getSurfaceBounds(pageRect);