Android: Get back scrim on navigation popup

This CL restores the missing scrim when there is a single entry on the
navigation sheet. The repro step is unique in that it's the only
situation where the sheet with a single entry "Show full history" is
displayed. All the others show at least 2.

The scrim didn't appear since BottomSheet didn't trigger the event
|onSheetOpened|. The minimum swipable state is set to
peek(https://crrev.com/c/1880495), but the sheet height with a single
entry is smaller than that of the peek state (1.5 x entry height),
therefore didn't meet the condition that fires the event.

To address the issue, following changes were made:

1) BottomSheetContent disables peek/half state for this occasion so
that the sheet can go straight to full state.

2) Skip calling |expandSheet| but used BottomSheetContent state info
to have the same effect. The explicit call to the API, when combined
with the above change, causes the same state transition (full ->
full), which cancels the animation effect.

Bug: 1020408
Change-Id: I2b9d3d2f495a167dd844be82b9796bfeeb2fda81
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1893129Reviewed-by: Matthew Jones <mdjones@chromium.org>
Commit-Queue: Jinsuk Kim <jinsukkim@chromium.org>
Cr-Commit-Position: refs/heads/master@{#711919}

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

@@ -140,7 +140,7 @@ class NavigationSheetCoordinator implements BottomSheetContent, NavigationSheet
             return mLayoutInflater.inflate(R.layout.navigation_popup_item, null);
         }, NavigationItemViewBinder::bind);
         mOpenSheetRunnable = () -> {
-            if (isHidden()) openSheet(false, true);
+            if (isHidden()) openSheet(true, true);
         };
         mLongSwipePeekThreshold = Math.min(
                 context.getResources().getDisplayMetrics().density * LONG_SWIPE_PEEK_THRESHOLD_DP,
@@ -156,7 +156,7 @@ class NavigationSheetCoordinator implements BottomSheetContent, NavigationSheet
     }
 
     // Transition to either peeked or expanded state.
-    private boolean openSheet(boolean fullyExpand, boolean animate) {
+    private boolean openSheet(boolean expandIfSmall, boolean animate) {
         mContentView =
                 (NavigationSheetView) mLayoutInflater.inflate(R.layout.navigation_sheet, null);
         ListView listview = (ListView) mContentView.findViewById(R.id.navigation_entries);
@@ -170,8 +170,10 @@ class NavigationSheetCoordinator implements BottomSheetContent, NavigationSheet
         }
         mBottomSheetController.get().addObserver(mSheetObserver);
         mSheetTriggered = true;
-        mFullyExpand = fullyExpand;
-        if (fullyExpand || history.getEntryCount() <= SKIP_PEEK_COUNT) expandSheet();
+        if (expandIfSmall && history.getEntryCount() <= SKIP_PEEK_COUNT) {
+            mFullyExpand = true;
+            expandSheet();
+        }
         return true;
     }
 
@@ -188,6 +190,7 @@ class NavigationSheetCoordinator implements BottomSheetContent, NavigationSheet
         mForward = forward;
         mShowCloseIndicator = showCloseIndicator;
         mSheetTriggered = false;
+        mFullyExpand = false;
         mOpenedAsPopup = false;
     }
 
@@ -195,7 +198,11 @@ class NavigationSheetCoordinator implements BottomSheetContent, NavigationSheet
     public boolean startAndExpand(boolean forward, boolean animate) {
         start(forward, /* showCloseIndicator= */ false);
         mOpenedAsPopup = true;
-        boolean opened = openSheet(/* fullyExpand= */ true, animate);
+
+        // Enter the expanded state by disabling peek/half state rather than
+        // calling |expandSheet| explicilty. Otherwise it cause an extra
+        // state transition (full -> full), which cancels the animation effect.
+        boolean opened = openSheet(/* expandIfSmall */ false, animate);
         if (opened) GestureNavMetrics.recordUserAction("Popup");
         return opened;
     }
@@ -305,6 +312,7 @@ class NavigationSheetCoordinator implements BottomSheetContent, NavigationSheet
 
     @Override
     public int getPeekHeight() {
+        if (mOpenedAsPopup) return BottomSheetContent.HeightMode.DISABLED;
         // Makes peek state as 'not present' when bottom sheet is in expanded state (i.e. animating
         // from expanded to close state). It avoids the sheet animating in two distinct steps, which
         // looks awkward.
@@ -315,8 +323,8 @@ class NavigationSheetCoordinator implements BottomSheetContent, NavigationSheet
 
     @Override
     public float getHalfHeightRatio() {
-        return mFullyExpand ? getFullHeightRatio()
-                            : getCappedHeightRatio(mParentView.getHeight() / 2 + mItemHeight / 2);
+        if (mOpenedAsPopup) return BottomSheetContent.HeightMode.DISABLED;
+        return getCappedHeightRatio(mParentView.getHeight() / 2 + mItemHeight / 2);
     }
 
     @Override