Revise the shelf alignment locking mechanism.

ash/shelf/shelf_view_unittest.cc

Index: ash/shelf/shelf_view_unittest.cc
diff --git a/ash/shelf/shelf_view_unittest.cc b/ash/shelf/shelf_view_unittest.cc
index afb511795271ed0eabe938e51a11e2616f09ab50..a4e01c7844523031d4e33546f8cbc1a1be3fd9a7 100644
--- a/ash/shelf/shelf_view_unittest.cc
+++ b/ash/shelf/shelf_view_unittest.cc
@@ -962,9 +962,8 @@ TEST_F(ShelfViewTest, AssertNoButtonsOverlap) {
   // Test that any two successive visible icons never overlap in all shelf
   // alignment types.
   const ShelfAlignment kAlignments[] = {
-      SHELF_ALIGNMENT_LEFT,
-      SHELF_ALIGNMENT_RIGHT,
-      SHELF_ALIGNMENT_BOTTOM
+      SHELF_ALIGNMENT_LEFT, SHELF_ALIGNMENT_RIGHT, SHELF_ALIGNMENT_BOTTOM,
+      SHELF_ALIGNMENT_LOCKED,
   };
 
   for (ShelfAlignment alignment : kAlignments) {
@@ -987,12 +986,15 @@ TEST_F(ShelfViewTest, AssertNoButtonsOverlap) {
 // Making sure the overflow bubble arrow correctly tracks with shelf position.
 TEST_F(ShelfViewTest, OverflowArrowForShelfPosition) {
   const ShelfAlignment kAlignments[] = {
-      SHELF_ALIGNMENT_BOTTOM, SHELF_ALIGNMENT_LEFT, SHELF_ALIGNMENT_RIGHT};
+      SHELF_ALIGNMENT_BOTTOM, SHELF_ALIGNMENT_LEFT, SHELF_ALIGNMENT_RIGHT,
+      SHELF_ALIGNMENT_LOCKED,
+  };
 
   // These must match what is expected for each alignment above.
   const views::BubbleBorder::Arrow kArrows[] = {
       views::BubbleBorder::BOTTOM_LEFT, views::BubbleBorder::LEFT_TOP,
-      views::BubbleBorder::RIGHT_TOP};
+      views::BubbleBorder::RIGHT_TOP, views::BubbleBorder::BOTTOM_LEFT,
+  };
 
   for (size_t i = 0; i < arraysize(kAlignments); i++) {
     shelf_view_->shelf()->SetAlignment(kAlignments[i]);