minor tweak to mdc chips adapter for latest upstream update to unbreak pantheon

angular already manages focus fully and this hook does negligible good and a lot of harm (e.g., focusing thigns that were never meant to be focused). long term we probably want to consolidate the code, but for now just keep it unbroken.

squash this commit into the main PR

Author: stevenyxu

src/material-experimental/mdc-chips/chip.ts

@@ -249,8 +249,8 @@ export class MatChip extends _MatChipMixinBase implements AfterContentInit, Afte
       // specify whether selection occurred via user input.
     },
     notifyNavigation: () => {
-      // TODO: This is a new feature added by MDC, consider exposing this event to users in the
-      //  future.
+      // TODO: This is a new feature added by MDC; consider exposing this event to users in the
+      // future.
     },
     notifyTrailingIconInteraction: () => this.removeIconInteraction.emit(this.id),
     notifyRemoval: () => this.removed.emit({chip: this}),
@@ -262,8 +262,11 @@ export class MatChip extends _MatChipMixinBase implements AfterContentInit, Afte
     hasLeadingIcon: () => !!this.leadingIcon,
     hasTrailingAction: () => !!this.trailingIcon,
     isRTL: () => !!this._dir && this._dir.value === 'rtl',
-    focusPrimaryAction: () => this._elementRef.nativeElement.focus(),
-    focusTrailingAction: () => this.trailingIcon && this.trailingIcon.focus(),
+    focusPrimaryAction: () => {
+      // Angular Material MDC chips fully manage focus. TODO: Managing focus and handling keyboard
+      // events was added by MDC after our implementation; consider consolidating.
+    },
+    focusTrailingAction: () => {},
     setTrailingActionAttr: (attr, value) =>
         this.trailingIcon && this.trailingIcon.setAttribute(attr, value),
     setPrimaryActionAttr: (name: string, value: string) => {