Scanning: Add skeleton for shared css

Bug: 1059779
Test: browser_tests --gtest_filter=ScanningUIBrowserTest.All
Change-Id: Ia69f55232fc5e0065d646363798f545f6a1eeb28
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2500421Reviewed-by: Zentaro Kavanagh <zentaro@chromium.org>
Commit-Queue: Michael Checo <michaelcheco@google.com>
Cr-Commit-Position: refs/heads/master@{#821007}

chromeos/components/scanning/resources/BUILD.gn

@@ -125,6 +125,7 @@ html_to_js("web_components") {
     "scan_settings_section.js",
     "scanner_select.js",
     "scanning_app.js",
+    "scanning_shared_css.js",
     "source_select.js",
     "throbber_css.js",
   ]

chromeos/components/scanning/resources/index.html

@@ -12,6 +12,7 @@
 
     <script type="module" src="scanning_app.js"></script>
     <script type="module" src="mojo_interface_provider.js"></script>
+    <link rel="stylesheet" src="scanning_shared_css.js"></script>
     <!-- Below mojo script required to run browser tests -->
     <script src="chrome://resources/mojo/mojo/public/js/mojo_bindings_lite.js">
     </script>

chromeos/components/scanning/resources/scanning_app_resources.grd

@@ -30,6 +30,7 @@
       <include name="IDR_SCANNING_APP_RESOLUTION_SELECT_JS" file="${root_gen_dir}/chromeos/components/scanning/resources/resolution_select.js" use_base_dir="false" type="BINDATA"/>
       <include name="IDR_SCANNING_APP_SCAN_SETTINGS_SECTION_JS" file="${root_gen_dir}/chromeos/components/scanning/resources/scan_settings_section.js" use_base_dir="false" type="BINDATA"/>
       <include name="IDR_SCANNING_APP_THROBBER_CSS_JS" file="${root_gen_dir}/chromeos/components/scanning/resources/throbber_css.js" use_base_dir="false" type="BINDATA"/>
+      <include name="IDR_SCANNING_APP_SCANNING_SHARED_CSS_JS" file="${root_gen_dir}/chromeos/components/scanning/resources/scanning_shared_css.js" use_base_dir="false" type="BINDATA"/>
       <include name="IDR_SCANNING_APP_ICON_16" file="scanning_app_icon_16.png" type="BINDATA" />
       <include name="IDR_SCANNING_APP_ICON_32" file="scanning_app_icon_32.png" type="BINDATA" />
       <include name="IDR_SCANNING_APP_ICON_48" file="scanning_app_icon_48.png" type="BINDATA" />

chromeos/components/scanning/resources/scanning_shared_css.html

+<link rel="stylesheet"
+    href="chrome://resources/chromeos/colors/cros_colors.generated.css">
+<link rel="stylesheet" href="chrome://resources/css/text_defaults_md.css">
+<link rel="stylesheet" href="chrome://resources/css/md_colors.css">
+<template>
+  <style include="cr-shared-style">
+    html {
+      background-color: var(--cros-bg-color);
+    }
+  </style>
+</template>

chromeos/components/scanning/resources/scanning_shared_css.js

+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'chrome://resources/cr_elements/shared_style_css.m.js';
+import 'chrome://resources/cr_elements/shared_vars_css.m.js';
+import 'chrome://resources/polymer/v3_0/polymer/polymer_bundled.min.js';
+
+const template = document.createElement('template');
+template.innerHTML = `
+<dom-module id="scanning-shared">{__html_template__}</dom-module>
+`;
+document.body.appendChild(template.content.cloneNode(true));
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