add more m2- prefixes to missing APIs

Author: andrewseguin

tensorboard/webapp/theme/_tb_theme.template.scss

@@ -52,19 +52,19 @@ $tb-theme: /*m2*/ mat.define-light-theme(
 
 // Overriding mat-light-theme-foreground variables.
 $tb-foreground: map_merge(
-  mat.$light-theme-foreground-palette,
+  /*m2$*/ mat.$light-theme-foreground-palette,
   (
-    text: /*m2*/ mat.get-color-from-palette(mat.$gray-palette, 900),
-    secondary-text: /*m2*/ mat.get-color-from-palette(mat.$gray-palette, 700),
-    disabled-text: /*m2*/ mat.get-color-from-palette(mat.$gray-palette, 600),
+    text: /*m2*/ mat.get-color-from-palette(/*m2$*/ mat.$gray-palette, 900),
+    secondary-text: /*m2*/ mat.get-color-from-palette(/*m2$*/ mat.$gray-palette, 700),
+    disabled-text: /*m2*/ mat.get-color-from-palette(/*m2$*/ mat.$gray-palette, 600),
     // TB specific variable.
     border: #ebebeb,
-    link: /*m2*/ mat.get-color-from-palette(mat.$blue-palette, 700),
-    link-visited: /*m2*/ mat.get-color-from-palette(mat.$purple-palette, 700),
+    link: /*m2*/ mat.get-color-from-palette(/*m2$*/ mat.$blue-palette, 700),
+    link-visited: /*m2*/ mat.get-color-from-palette(/*m2$*/ mat.$purple-palette, 700),
   )
 );
 $tb-background: map_merge(
-  mat.$light-theme-background-palette,
+  /*m2*/ mat.$light-theme-background-palette,
   (
     app-bar: $tb-app-bar-color,
     // Default is `map.get($grey-palette, 50)`.
@@ -94,7 +94,7 @@ $tb-theme: map_merge(
   )
 );
 
-$tb-dark-theme: mat.define-dark-theme(
+$tb-dark-theme: /*m2*/ mat.define-dark-theme(
   (
     color: (
       primary: $tb-dark-primary,
@@ -109,9 +109,9 @@ $tb-dark-foreground: map_merge(
   map-get(/*m2*/ mat.get-color-config($tb-dark-theme), foreground),
   (
     border: #555,
-    disabled-text: /*m2*/ mat.get-color-from-palette(mat.$gray-palette, 700),
-    link: /*m2*/ mat.get-color-from-palette(mat.$blue-palette, 400),
-    link-visited: /*m2*/ mat.get-color-from-palette(mat.$purple-palette, 300),
+    disabled-text: /*m2*/ mat.get-color-from-palette(/*m2$*/ mat.$gray-palette, 700),
+    link: /*m2*/ mat.get-color-from-palette(/*m2$*/ mat.$blue-palette, 400),
+    link-visited: /*m2*/ mat.get-color-from-palette(/*m2$*/ mat.$purple-palette, 300),
   )
 );
 $tb-dark-background: map_merge(