gr-button.remove use ::part() instead of @apply

Since @apply was never approved and it is broken in lit2

Change-Id: I51850b0baad1400bc540dd6462d81f035ab4aa2d
diff --git a/polygerrit-ui/app/elements/shared/gr-account-chip/gr-account-chip.ts b/polygerrit-ui/app/elements/shared/gr-account-chip/gr-account-chip.ts
index 65de971..a3650b1 100644
--- a/polygerrit-ui/app/elements/shared/gr-account-chip/gr-account-chip.ts
+++ b/polygerrit-ui/app/elements/shared/gr-account-chip/gr-account-chip.ts
@@ -133,23 +133,21 @@
         .container {
           --account-label-padding-horizontal: 6px;
         }
-        gr-button.remove,
-        gr-button.remove:hover,
-        gr-button.remove:focus {
-          --gr-button: {
-            border-top-width: 0;
-            border-right-width: 0;
-            border-bottom-width: 0;
-            border-left-width: 0;
-            color: var(--deemphasized-text-color);
-            font-weight: var(--font-weight-normal);
-            height: 0.6em;
-            line-height: 10px;
-            /* This cancels most of the --account-label-padding-horizontal. */
-            margin-left: -4px;
-            padding: 0 2px 0 0;
-            text-decoration: none;
-          }
+        gr-button.remove::part(paper-button),
+        gr-button.remove:hover::part(paper-button),
+        gr-button.remove:focus::part(paper-button) {
+          border-top-width: 0;
+          border-right-width: 0;
+          border-bottom-width: 0;
+          border-left-width: 0;
+          color: var(--deemphasized-text-color);
+          font-weight: var(--font-weight-normal);
+          height: 0.6em;
+          line-height: 10px;
+          /* This cancels most of the --account-label-padding-horizontal. */
+          margin-left: -4px;
+          padding: 0 2px 0 0;
+          text-decoration: none;
         }
       </style>
     `;
diff --git a/polygerrit-ui/app/elements/shared/gr-button/gr-button_html.ts b/polygerrit-ui/app/elements/shared/gr-button/gr-button_html.ts
index a174627..a15b560 100644
--- a/polygerrit-ui/app/elements/shared/gr-button/gr-button_html.ts
+++ b/polygerrit-ui/app/elements/shared/gr-button/gr-button_html.ts
@@ -169,7 +169,12 @@
       border-top-color: var(--deemphasized-text-color);
     }
   </style>
-  <paper-button raised="[[!link]]" disabled="[[_disabled]]" tabindex="-1">
+  <paper-button
+    raised="[[!link]]"
+    disabled="[[_disabled]]"
+    tabindex="-1"
+    part="paper-button"
+  >
     <template is="dom-if" if="[[loading]]">
       <span class="loadingSpin"></span>
     </template>
diff --git a/polygerrit-ui/app/elements/shared/gr-linked-chip/gr-linked-chip.ts b/polygerrit-ui/app/elements/shared/gr-linked-chip/gr-linked-chip.ts
index 3fdf4eb..b74d643 100644
--- a/polygerrit-ui/app/elements/shared/gr-linked-chip/gr-linked-chip.ts
+++ b/polygerrit-ui/app/elements/shared/gr-linked-chip/gr-linked-chip.ts
@@ -89,22 +89,20 @@
     // in <style> inside the template.
     const customStyle = html`
       <style>
-        gr-button.remove,
-        gr-button.remove:hover,
-        gr-button.remove:focus {
-          --gr-button: {
-            border-top-width: 0;
-            border-right-width: 0;
-            border-bottom-width: 0;
-            border-left-width: 0;
-            color: var(--deemphasized-text-color);
-            font-weight: var(--font-weight-normal);
-            height: 0.6em;
-            line-height: 10px;
-            margin-left: var(--spacing-xs);
-            padding: 0;
-            text-decoration: none;
-          }
+        gr-button::part(paper-button),
+        gr-button.remove:hover::part(paper-button),
+        gr-button.remove:focus::part(paper-button) {
+          border-top-width: 0;
+          border-right-width: 0;
+          border-bottom-width: 0;
+          border-left-width: 0;
+          color: var(--deemphasized-text-color);
+          font-weight: var(--font-weight-normal);
+          height: 0.6em;
+          line-height: 10px;
+          margin-left: var(--spacing-xs);
+          padding: 0;
+          text-decoration: none;
         }
       </style>
     `;