WebUI: Remove unnecessary usage of paper-button CSS mixins.

Bug: 832173
Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Change-Id: I982e24b7234617b111e7adfa3c0f83356722ec8d
Reviewed-on: https://chromium-review.googlesource.com/1013280Reviewed-by: Hector Carmona <hcarmona@chromium.org>
Commit-Queue: Demetrios Papadopoulos <dpapad@chromium.org>
Cr-Commit-Position: refs/heads/master@{#551209}

chrome/browser/resources/settings/basic_page/basic_page.html

@@ -43,9 +43,6 @@
       }
 
       #advancedToggle {
-        --paper-button: {
-          text-transform: none;
-        }
         @apply --settings-actionable;
         align-items: center;
         display: flex;
@@ -53,6 +50,7 @@
         margin-top: 12px;  /* Part of a 48px spacer (33px + 12px + 3px). */
         min-height: 32px;
         padding: 0 12px;
+        text-transform: none;
       }
 
       #secondaryUserBanner {

chrome/browser/resources/settings/settings_shared_css.html

@@ -70,12 +70,10 @@
       }
 
       /* Customize the disabled state of paper buttons within a settings box. */
-      .settings-box paper-button {
-        --paper-button-disabled: {
-          background: none;
-          color: black;
-          opacity: 0.26;
-        };
+      .settings-box paper-button[disabled] {
+        background: none;
+        color: black;
+        opacity: 0.26;
       }
 
       /* For "Advanced" toggle button. */

ui/webui/resources/cr_elements/cr_profile_avatar_selector/cr_profile_avatar_selector.html

@@ -16,12 +16,10 @@
       }
 
       #avatar-grid .avatar {
-        --paper-button: {
-          background: var(--paper-grey-300);
-        };
         --paper-button-flat-keyboard-focus: {
           background: var(--paper-grey-400);
         };
+        background-color: var(--paper-grey-300);
         background-position: center;
         background-repeat: no-repeat;
         border: 1px solid rgba(0, 0, 0, .12);

ui/webui/resources/cr_elements/paper_button_style_css.html

@@ -8,20 +8,18 @@
   <template>
     <style>
       paper-button {
-        --paper-button: {
-          -webkit-padding-end: var(--cr-button-edge-spacing);
-          -webkit-padding-start: var(--cr-button-edge-spacing);
-          color: var(--paper-grey-600);
-          font-weight: 500;
-          min-width: 1em;  /* A tighter fit than 5.14em for short buttons. */
-          text-decoration: none;
-        };
         --paper-button-flat-keyboard-focus: {
           background: rgba(0, 0, 0, .12);
         };
+        -webkit-padding-end: var(--cr-button-edge-spacing);
+        -webkit-padding-start: var(--cr-button-edge-spacing);
+        color: var(--paper-grey-600);
         flex-shrink: 0;
+        font-weight: 500;
         height: 36px;
         margin: 0;
+        min-width: 1em;  /* A tighter fit than 5.14em for short buttons. */
+        text-decoration: none;
       }
     </style>
   </template>