Enable high contrast mode for <select multiple>

This change updates forced_color.css to enable <select multiple> to
render high contrast color.

Bug: 994219
Change-Id: If9814a11544232cfe8ee4de219f0ddaa83f70204
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1816448
Commit-Queue: Alex Keng <shihken@microsoft.com>
Reviewed-by: Kent Tamura <tkent@chromium.org>
Reviewed-by: Mason Freed <masonfreed@chromium.org>
Cr-Commit-Position: refs/heads/master@{#699207}

third_party/blink/renderer/core/html/resources/forced_colors.css

@@ -106,6 +106,45 @@
     color: GrayText;
   }
 
+  select:-internal-list-box {
+    background-color: Window !important;
+    border-color: ButtonText;
+  }
+
+  /* option disabled */
+  select:-internal-list-box option:disabled,
+  select:-internal-list-box option:disabled:hover,
+  select:-internal-list-box:disabled option,
+  select:-internal-list-box:disabled option:hover {
+    background-color: Window !important;
+    color: GrayText !important;
+  }
+
+  /* option selected */
+  select:-internal-list-box:focus option:checked,
+  select:-internal-list-box:focus option:checked:hover,
+  select:-internal-list-box option:checked,
+  select:-internal-list-box option:checked:hover {
+    background-color: Window !important;
+    color: Highlight !important;
+  }
+
+  /* option both disabled and selected */
+  select:-internal-list-box:focus option:checked:disabled,
+  select:-internal-list-box:focus option:checked:disabled:hover,
+  select:-internal-list-box:disabled option:checked,
+  select:-internal-list-box:disabled option:checked:hover,
+  select:-internal-list-box option:checked:disabled,
+  select:-internal-list-box option:checked:disabled:hover {
+    background-color: Window !important;
+    color: GrayText !important;
+  }
+
+  select:-internal-list-box option:hover {
+    background-color: Window;
+    color: Highlight;
+  }
+
   select {
     background: Window;
     border-color: WindowText;

third_party/blink/web_tests/fast/forms/controls-new-ui-high-contrast/select.html

+<select multiple>
+  <option selected>first selected</option>
+  <option>unselected</option>
+  <option selected>second selected</option>
+  <option disabled>disabled</option>
+</select><br><br>
+<script>
+if (window.testRunner)
+  testRunner.setUseMockTheme(false);
+</script>
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