Consider bottom sheet closing state when picking a snackbar manager

This patch has ChromeActivity consider whether the bottom sheet is in
the process of closing before determining which container to place
a snackbar in. This avoids inadvertently blocking snackbars that are
shown when the sheet is about closed.

Bug: 950739
Change-Id: Ib7e0b3d2bbd58580dad84c2d146b13b98dcb13ba
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1559154Reviewed-by: Theresa <twellington@chromium.org>
Commit-Queue: Matthew Jones <mdjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#649134}

chrome/android/java/src/org/chromium/chrome/browser/ChromeActivity.java

@@ -1436,10 +1436,11 @@ public abstract class ChromeActivity<C extends ChromeActivityComponent>
      */
     @Override
     public SnackbarManager getSnackbarManager() {
-        return mBottomSheetController != null
-                        && mBottomSheetController.getBottomSheet().isSheetOpen()
-                ? mBottomSheetController.getSnackbarManager()
-                : mSnackbarManager;
+        boolean useBottomSheetContainer = mBottomSheetController != null
+                && mBottomSheetController.getBottomSheet().isSheetOpen()
+                && !mBottomSheetController.getBottomSheet().isClosing();
+        return useBottomSheetContainer ? mBottomSheetController.getSnackbarManager()
+                                       : mSnackbarManager;
     }
 
     @Override

chrome/android/java/src/org/chromium/chrome/browser/widget/bottomsheet/BottomSheet.java

@@ -472,6 +472,13 @@ public class BottomSheet
         return mActionBarDelegate;
     }
 
+    /**
+     * @return Whether the sheet is in the process of closing.
+     */
+    public boolean isClosing() {
+        return mSettleAnimator != null && mTargetState == SheetState.HIDDEN;
+    }
+
     @Override
     public boolean onInterceptTouchEvent(MotionEvent e) {
         // If touch is disabled, act like a black hole and consume touch events without doing