[Android] Request layouting after hiding keyboard replacement

The compositor viewholder relies on a layout change as signal that the
keyboard might have changed its state.
As the accessory doesn't emit this by default (because the activity
remains of the same size), emit this signal when the keyboard would
trigger it.

Bug: 900510
Change-Id: I9f78661f9835b6d04b202ea8dbd02df77d402b54
Reviewed-on: https://chromium-review.googlesource.com/c/1317913Reviewed-by: Ioana Pandele <ioanap@chromium.org>
Commit-Queue: Friedrich Horschig [CET] <fhorschig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#605353}

chrome/android/java/src/org/chromium/chrome/browser/autofill/keyboard_accessory/ManualFillingMediator.java

@@ -325,6 +325,7 @@ class ManualFillingMediator extends EmptyTabObserver
         mKeyboardAccessory.closeActiveTab();
         mKeyboardAccessory.setBottomOffset(0);
         mAccessorySheet.hide();
+        mActivity.getCompositorViewHolder().requestLayout(); // Request checks for keyboard changes.
     }
 
     /**