Import MDC Web v0.38.0. This includes adding experimental list templates as well as the changes from all of the releases listed below.

0.38.0 (2018-07-30)
Bug Fixes
chips: Remove color change from selected filter chips (#3093) (19e3d7f)
infrastructure: Rework goog.module positioning (#3098) (fbbf58a)
theme: Allow CSS variables to be passed to mdc-theme-prop (#3086) (b47fe7d)

Code Refactoring
chips: Register handlers in component instead of foundation (#3146) (36e2755)

Features
floating-label: Add max-width mixin (#2956) (66f8bf7)
icon-button: update event handling to new standard (#3165) (531867e)
list: Add single selection (#2970) (cd1f972)
list: Updated two-line list to use typography baseline to match spec. (#3085) (4d11b37)
switch: Merge updated switch into master (#3214) (19724f1), closes #2825
typography: New mixin to set exact baseline height of text elements. (#3083) (dd3817a)

BREAKING CHANGES
switch: MDC Switch DOM structure and Sass APIs have changed, and JavaScript APIs have been added. See the documentation for more information.
icon-button: Removed some adapter APIs (registerInteractionHandler, deregisterInteractionHandler) and shifted responsibility of event handling out of the foundation and into the component.
chips: MDCChip/MDCChipSet registerEventHandler adapter methods were removed, and corresponding handlers were made public in MDCChipFoundation/MDCChipSetFoundation.

0.37.1 (2018-07-16)
Bug Fixes
hot-patching closure annotations. (#3024) (d5b95ab)
button: Remove dense/stroked line-height tweaks to improve alignment (#3028) (8b5f595)
notched-outline: Remove unused dependency from scss (#3044) (85ecf11)
typography: Update variable reference to work for newer versions of ruby-sass (#3047) (0dfad9a)

0.37.0 (2018-07-02)
Bug Fixes
chips: Add an event typedef for chip interaction events (#2965) (153e737)
icon-button: Remove unused styles, update docs, code cleanup (#2957) (32b5b9d)

Features
chips: Expose method to begin chip exit animation (#2845) (eb00fd3)
chips: Make chip exit on trailing icon click optional (#2893) (9178d46)
chips: Make event handlers on Chip public (#2997) (963e0c1)
fab: Add Extended FAB (14cb0bf)
fab: Enable padding customization (#2959) (1f5fd1f)
list: Add arrow key a11y support. (#2871) (7c06e9f)
ripple: Expose focus/blur handlers (#2905) (31d81ad)

0.36.1 (2018-06-18)
Bug Fixes
checkbox: support high contrast mode in Firefox on Windows (#2927) (8b7d77e)
menu: Update adapter to check for focus before calling (#2880) (84fcc08)
text-field: Hide extraneous border in FF in HC mode. (#2931) (bd4c563)
PiperOrigin-RevId: 209690562

Author: Googler

lib/css/mdc_web/elevation/_mixins.scss

@@ -30,13 +30,7 @@
     @error "$z-value must be between 0 and 24, but received '#{$z-value}'";
   }
 
-  @if map-has-key($mdc-theme-property-values, $color) {
-    $color: map-get($mdc-theme-property-values, $color);
-  }
-
-  @if type-of($color) != color {
-    @error "$color must be a valid color, but '#{$color}' is of type #{type-of($color)}";
-  }
+  $color: mdc-theme-prop-value($color);
 
   $umbra-z-value: map-get($mdc-elevation-umbra-map, $z-value);
   $penumbra-z-value: map-get($mdc-elevation-penumbra-map, $z-value);

lib/css/mdc_web/theme/_mixins.scss

@@ -18,11 +18,11 @@
 
 // Applies the correct theme color style to the specified property.
 // $property is typically color or background-color, but can be any CSS property that accepts color values.
-// $style should be one of the map keys in $mdc-theme-property-values (_variables.scss), or a literal color value.
+// $style should be one of the map keys in $mdc-theme-property-values (_variables.scss), or a color value.
 // $edgeOptOut controls whether to feature-detect around Edge to avoid emitting CSS variables for it,
 // intended for use in cases where interactions with pseudo-element styles cause problems due to Edge bugs.
 @mixin mdc-theme-prop($property, $style, $important: false, $edgeOptOut: false) {
-  @if type-of($style) == "color" or $style == "currentColor" {
+  @if mdc-theme-is-valid-theme-prop-value_($style) {
     @if $important {
       #{$property}: $style !important;
     } @else {

lib/css/mdc_web/theme/_variables.scss

@@ -105,28 +105,28 @@ $mdc-theme-property-values: (
   text-icon-on-dark: mdc-theme-ink-color-for-fill_(icon, dark)
 );
 
-// If `$property` is a literal color value (e.g., `blue`, `#fff`), it is returned verbatim. Otherwise, the value of the
-// corresponding theme property (from `$mdc-theme-property-values`) is returned. If `$property` is not a color and no
-// such theme property exists, an error is thrown.
+// If `$style` is a color (a literal color value, `currentColor`, or a CSS custom property), it is returned verbatim.
+// Otherwise, `$style` is treated as a theme property name, and the corresponding value from
+// `$mdc-theme-property-values` is returned. If this also fails, an error is thrown.
 //
 // This is mainly useful in situations where `mdc-theme-prop` cannot be used directly (e.g., `box-shadow`).
 //
 // Examples:
 //
-// 1. mdc-theme-prop-value(primary) => "#3f51b5"
+// 1. mdc-theme-prop-value(primary) => "#6200ee"
 // 2. mdc-theme-prop-value(blue)    => "blue"
 //
 // NOTE: This function must be defined in _variables.scss instead of _functions.scss to avoid circular imports.
-@function mdc-theme-prop-value($property) {
-  @if type-of($property) == "color" or $property == "currentColor" {
-    @return $property;
+@function mdc-theme-prop-value($style) {
+  @if mdc-theme-is-valid-theme-prop-value_($style) {
+    @return $style;
   }
 
-  @if not map-has-key($mdc-theme-property-values, $property) {
-    @error "Invalid theme property: '#{$property}'. Choose one of: #{map-keys($mdc-theme-property-values)}";
+  @if not map-has-key($mdc-theme-property-values, $style) {
+    @error "Invalid theme property: '#{$style}'. Choose one of: #{map-keys($mdc-theme-property-values)}";
   }
 
-  @return map-get($mdc-theme-property-values, $property);
+  @return map-get($mdc-theme-property-values, $style);
 }
 
 // NOTE: This function must be defined in _variables.scss instead of _functions.scss to avoid circular imports.
@@ -140,3 +140,8 @@ $mdc-theme-property-values: (
 
   @return map-get($color-map-for-tone, $text-style);
 }
+
+// NOTE: This function is depended upon by mdc-theme-prop-value (above) and thus must be defined in this file.
+@function mdc-theme-is-valid-theme-prop-value_($style) {
+  @return type-of($style) == "color" or $style == "currentColor" or str_slice($style, 1, 4) == "var(";
+}