Fix thumbnail disappearing during staged split animation

Previous set the thumbnail view to be visible initially. After deciding not to do so, forgot to put the visibility statement back. Also the transform matrix needs to reset before posting new scales.

Test: https://recall.googleplex.com/projects/f46cfe9c-8076-4efe-bf8a-b1cc4f1f5e1b/sessions/6576df3a-6d14-4b7e-8fb2-1c0a335472e4
Fixes: 194414938
Change-Id: I25fe39ea99943a3c1e2257681df3eb379bc30e51
diff --git a/quickstep/src/com/android/quickstep/views/FloatingTaskThumbnailView.java b/quickstep/src/com/android/quickstep/views/FloatingTaskThumbnailView.java
index 98e50f6..d869fed 100644
--- a/quickstep/src/com/android/quickstep/views/FloatingTaskThumbnailView.java
+++ b/quickstep/src/com/android/quickstep/views/FloatingTaskThumbnailView.java
@@ -62,6 +62,7 @@
 
         // Scale down the bitmap to fix x, and crop in y.
         float scale = 1.0f * getMeasuredWidth() / mBitmap.getWidth();
+        mMatrix.reset();
         mMatrix.postScale(scale, scale);
         mBitmapShader.setLocalMatrix(mMatrix);
 
diff --git a/quickstep/src/com/android/quickstep/views/FloatingTaskView.java b/quickstep/src/com/android/quickstep/views/FloatingTaskView.java
index 93a3a9f..fe5e1d0 100644
--- a/quickstep/src/com/android/quickstep/views/FloatingTaskView.java
+++ b/quickstep/src/com/android/quickstep/views/FloatingTaskView.java
@@ -91,6 +91,8 @@
         // Copy bounds of exiting thumbnail into ImageView
         mThumbnailView.setThumbnail(thumbnail);
 
+        mThumbnailView.setVisibility(VISIBLE);
+
         RecentsView recentsView = launcher.getOverviewPanel();
         mOrientationHandler = recentsView.getPagedOrientationHandler();
         mSplitPlaceholderView.setIcon(icon,