refactor(benchmarks): simplify and clean up code

* Remove genrule to create styles.css
* Import indigo-pink.scss via CheckboxBenchmarkApp's styleUrls
* Set the view encapsulation of CheckboxBenchmarkApp to none so that the styles from indigo-pink.scss are applied to the whole page
* Remove some unused imports
* Add a comment to WORKSPACE to clarify what browser_repositories does
* Change CheckboxBenchmarkApp's mat-checkbox so that indeterminate is a one-way binding

Author: wagnermaciel

WORKSPACE

@@ -132,4 +132,5 @@ rbe_autoconfig(
 
 load("@npm_angular_dev_infra_private//benchmark/browsers:browser_repositories.bzl", "browser_repositories")
 
+# Load pinned rules_webtesting browser versions for tests.
 browser_repositories()

test/benchmarks/material/checkbox/BUILD.bazel

@@ -1,12 +1,5 @@
 load("@npm_angular_dev_infra_private//benchmark/component_benchmark:component_benchmark.bzl", "component_benchmark")
 
-genrule(
-    name = "indigo-pink",
-    srcs = ["//src/material/core:theming/prebuilt/indigo-pink.css"],
-    outs = ["styles.css"],
-    cmd = "cp $< $@",
-)
-
 # todo(wagnermaciel): If assets are defined and no index.html is provided, throw error with clear error message.
 component_benchmark(
     name = "benchmark",
@@ -23,6 +16,5 @@ component_benchmark(
 				"//src/cdk/a11y",
     ],
 		ng_srcs = [":app.module.ts"],
-    styles = [":indigo-pink"],
     prefix = "",
 )

test/benchmarks/material/checkbox/app.module.ts

@@ -6,9 +6,9 @@
  * found in the LICENSE file at https://angular.io/license
  */
 import { A11yModule } from '@angular/cdk/a11y';
-import { Component, NgModule, ViewChild } from '@angular/core';
+import { Component, NgModule, ViewEncapsulation } from '@angular/core';
 import { BrowserModule } from '@angular/platform-browser';
-import { MatCheckboxModule, MatCheckbox } from '@angular/material/checkbox';
+import { MatCheckboxModule } from '@angular/material/checkbox';
 
 /**
  * @title Checkbox benchmark component.
@@ -23,12 +23,13 @@ import { MatCheckboxModule, MatCheckbox } from '@angular/material/checkbox';
     <ng-container *ngIf="isVisible">
       <mat-checkbox
         [checked]="isChecked"
-        [(indeterminate)]="isIndeterminate"
+        [indeterminate]="isIndeterminate"
         (change)="toggleIsChecked()"
         >Check me!</mat-checkbox>
     </ng-container>
   `,
-  styles: [],
+  encapsulation: ViewEncapsulation.None,
+  styleUrls: ['//src/material/core/theming/prebuilt/indigo-pink.scss'],
 })
 export class CheckboxBenchmarkApp {
   isChecked = false;