Fix overtriggering of onTransitionPeekToHalf in BottomSheet

Overtriggering of the peek-to-half event would cause the scrim to
disappear when the device was rotated. This patch checks that the
sheet state is <= hidden (as opposed to just <) when blocking the
event's trigger. As an added precaution, the listener that sets the
scrim alpha has an added check for whether the sheet is open.

Bug: 840265
Change-Id: Ic3e0731be3525959898159e0610b3c49b9a04fa4
Reviewed-on: https://chromium-review.googlesource.com/1054210Reviewed-by: Theresa <twellington@chromium.org>
Commit-Queue: Matthew Jones <mdjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#557626}

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

@@ -1160,7 +1160,7 @@ public class BottomSheet extends FrameLayout
         float offsetWithBrowserControls = getCurrentOffsetPx() - getOffsetFromBrowserControls();
 
         // Do not send events for states less than the hidden state unless 0 has not been sent.
-        if (offsetWithBrowserControls < getSheetHeightForState(SHEET_STATE_HIDDEN)
+        if (offsetWithBrowserControls <= getSheetHeightForState(SHEET_STATE_HIDDEN)
                 && mLastOffsetRatioSent <= 0) {
             return;
         }

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

@@ -173,6 +173,7 @@ public class BottomSheetController implements ApplicationStatus.ActivityStateLis
 
             @Override
             public void onTransitionPeekToHalf(float transitionFraction) {
+                if (!mBottomSheet.isSheetOpen()) return;
                 fadingBackgroundView.setViewAlpha(transitionFraction);
             }