Android: Fix gesture navigation not working

Gesture navigation |getTargetOrCurrentState| regarded the state of
BottomSheet as NONE if it is not available yet. Previously the widget
was eagerly created the returned state was HIDDEN. Now BottomSheet
widget is lazily initialized, the method started returning NONE,
and it caused a bug not triggering the sheet at all. This CL fixes it
by defining the state of non-existing BottomSheet as HIDDEN.

Bug: 1020938
Change-Id: I460efcdceed29b5ae70249b7f6ace644afceeba4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1900506Reviewed-by: Matthew Jones <mdjones@chromium.org>
Reviewed-by: Jinsuk Kim <jinsukkim@chromium.org>
Commit-Queue: Jinsuk Kim <jinsukkim@chromium.org>
Cr-Commit-Position: refs/heads/master@{#712849}

chrome/android/java/src/org/chromium/chrome/browser/gesturenav/NavigationSheetCoordinator.java

@@ -264,7 +264,7 @@ class NavigationSheetCoordinator implements BottomSheetContent, NavigationSheet
 
     private @SheetState int getTargetOrCurrentState() {
         BottomSheet sheet = mBottomSheetController.get().getBottomSheet();
-        if (sheet == null) return BottomSheetController.SheetState.NONE;
+        if (sheet == null) return BottomSheetController.SheetState.HIDDEN;
         @SheetState
         int state = mBottomSheetController.get().getTargetSheetState();
         return state != BottomSheetController.SheetState.NONE