Log extra information on weird ToastManagerTest.PositionWithVisibleLeftShelf flake.

ash/system/toast/toast_manager_unittest.cc

Index: ash/system/toast/toast_manager_unittest.cc
diff --git a/ash/system/toast/toast_manager_unittest.cc b/ash/system/toast/toast_manager_unittest.cc
index 04d5355a6c373dbe5905adeefb4c91cacdfbd57b..f7e89f4b1811a2ad924f8aeca35671bdceaeb52f 100644
--- a/ash/system/toast/toast_manager_unittest.cc
+++ b/ash/system/toast/toast_manager_unittest.cc
@@ -235,7 +235,12 @@ TEST_F(ToastManagerTest, PositionWithVisibleLeftShelf) {
   EXPECT_FALSE(toast_bounds.Intersects(shelf_bounds));
   EXPECT_EQ(round(shelf_bounds.right() +
                   (root_bounds.width() - shelf_bounds.width()) / 2.0),
-            round(precise_toast_bounds.CenterPoint().x()));
+            round(precise_toast_bounds.CenterPoint().x()))
+      << "Shelf right bound: " << shelf_bounds.right()
+      << "\nRoot width: " << root_bounds.width()
+      << "\nShelf width: " << shelf_bounds.width()
+      << "\nPrecise toast center x position: "
+      << precise_toast_bounds.CenterPoint().x();
 }
 
 TEST_F(ToastManagerTest, PositionWithUnifiedDesktop) {