Change the overlay variable prefixes to cdk- and remove dependency on theming.

Author: crisbeto

src/lib/core/overlay/_overlay.scss

@@ -1,6 +1,4 @@
 @import '../style/variables';
-@import '../theming/palette';
-@import '../theming/theming';
 
 
 @mixin cdk-overlay() {
@@ -18,7 +16,7 @@
   // The overlay-container is an invisible element which contains all individual overlays.
   .cdk-overlay-container {
     position: fixed;
-    z-index: $md-z-index-overlay-container;
+    z-index: $cdk-z-index-overlay-container;
   }
 
   // We use an extra wrapper element in order to use make the overlay itself a flex item.
@@ -28,15 +26,15 @@
   .cdk-global-overlay-wrapper {
     display: flex;
     position: absolute;
-    z-index: $md-z-index-overlay;
+    z-index: $cdk-z-index-overlay;
   }
 
   // A single overlay pane.
   .cdk-overlay-pane {
     position: absolute;
     pointer-events: auto;
     box-sizing: border-box;
-    z-index: $md-z-index-overlay;
+    z-index: $cdk-z-index-overlay;
   }
 
   .cdk-overlay-backdrop {
@@ -47,7 +45,7 @@
     left: 0;
     right: 0;
 
-    z-index: $md-z-index-overlay-backdrop;
+    z-index: $cdk-z-index-overlay-backdrop;
     pointer-events: auto;
 
     // TODO(jelbourn): figure out if there are actually spec'ed colors for both light and dark
@@ -61,7 +59,7 @@
   }
 
   .cdk-overlay-dark-backdrop {
-    background: md-color($md-grey, 900); // TODO(crisbeto): make this theme-independent?
+    background: $cdk-overlay-dark-backdrop-background;
   }
 
   .cdk-overlay-transparent-backdrop {

src/lib/core/style/_variables.scss

@@ -22,9 +22,12 @@ $z-index-drawer: 100 !default;
 // We want overlays to always appear over user content, so set a baseline
 // very high z-index for the overlay container, which is where we create the new
 // stacking context for all overlays.
-$md-z-index-overlay-container: 1000;
-$md-z-index-overlay: 1000;
-$md-z-index-overlay-backdrop: 1;
+$cdk-z-index-overlay-container: 1000;
+$cdk-z-index-overlay: 1000;
+$cdk-z-index-overlay-backdrop: 1;
+
+// Background color for all of the backdrops
+$cdk-overlay-dark-backdrop-background: rgba(0, 0, 0, 0.6);
 
 
 // Global constants