Fix overlay image disappearing during flow.

Prior to this CL, the overlay image would disappear during the flow because the check to disambiguate between full and partial overlays was wrong.

Bug: 806868
Change-Id: Ice8e1bf16a4c077edea81f13fb97e286ef4a58a3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1948434
Auto-Submit: Clemens Arbesser <arbesser@google.com>
Reviewed-by: Mathias Carlen <mcarlen@chromium.org>
Commit-Queue: Mathias Carlen <mcarlen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#720933}

chrome/android/features/autofill_assistant/java/src/org/chromium/chrome/browser/autofill_assistant/overlay/AssistantOverlayDrawable.java

@@ -305,8 +305,8 @@ class AssistantOverlayDrawable extends Drawable implements FullscreenListener {
         canvas.drawPaint(mBackground);
 
         // Draw overlay image, if specified.
-        if (mTransparentArea.isEmpty() && mOverlayImage != null
-                && mOverlayImage.mImageBitmap != null && mOverlayImage.mImageSize != null) {
+        if (!mPartial && mOverlayImage != null && mOverlayImage.mImageBitmap != null
+                && mOverlayImage.mImageSize != null) {
             DisplayMetrics displayMetrics = mContext.getResources().getDisplayMetrics();
             int imageSize = mOverlayImage.mImageSize.getSizeInPixels(displayMetrics);
             int topMargin = 0;