Reset overscroll actions if no action is selected.

By quickly retrigger overscroll actions, you can be in a state where no
action is selected but offset is big enough to trigger action.
In this case, Overscroll action is stuck in this state.

Bug: 1003766
Change-Id: I2071a120e475bfc0bb95f2bddd216bbcb960f916
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2578984
Auto-Submit: Olivier Robin <olivierrobin@chromium.org>
Reviewed-by: Chris Lu <thegreenfrog@chromium.org>
Reviewed-by: Robbie Gibson <rkgibson@google.com>
Commit-Queue: Olivier Robin <olivierrobin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#836576}

ios/chrome/browser/ui/overscroll_actions/overscroll_actions_controller.mm

@@ -452,8 +452,12 @@ NSString* const kOverscrollActionsDidEnd = @"OverscrollActionsDidStop";
   self.scrollViewDragged = NO;
   // Content is now hidden behind toolbar, make sure that contentInset is
   // restored to initial value.
+  // If Overscroll actions are triggered and dismissed quickly, it is
+  // possible to be in a state where drag is enough to be in STARTED_PULLING
+  // or ACTION_READY state, but with no selectedAction.
   if (contentOffset.y >= 0 ||
-      self.overscrollState == OverscrollState::NO_PULL_STARTED) {
+      self.overscrollState == OverscrollState::NO_PULL_STARTED ||
+      self.overscrollActionView.selectedAction == OverscrollAction::NONE) {
     [self resetScrollViewTopContentInset];
   }