fix: public api surface fixes + stability markers

- ts-api-guardian will now error if a new public symbol is added with a stability marker (`@stable`, `@experimental`, `@deprecated`)
- DomEventsPlugin and KeyEventsPlugin were removed from public api surface - these classes is an implementation detail
- deprecated BROWSER_PROVIDERS was removed completely
- `@angular/compiler` was removed from the ts-api-guardian check since this package shouldn't contain anything that users need to directly import
- the rest of the api surface was conservatively marked as stable or experimental

BREAKING CHANGES: DomEventsPlugin and KeyEventsPlugin previously exported from core are no longer public - these classes are implementation detail.

Previously deprecated BROWSER_PROVIDERS was completely removed from platform-browser.

Closes #9236
Closes #9235
Ref #9234

modules/@angular/core/src/metadata.ts

@@ -30,6 +30,8 @@ import {Type} from '../src/facade/lang';
  * Interface for the {@link DirectiveMetadata} decorator function.
  *
  * See {@link DirectiveFactory}.
+ *
+ * @stable
  */
 export interface DirectiveDecorator extends TypeDecorator {}
 
@@ -37,6 +39,8 @@ export interface DirectiveDecorator extends TypeDecorator {}
  * Interface for the {@link ComponentMetadata} decorator function.
  *
  * See {@link ComponentFactory}.
+ *
+ * @stable
  */
 export interface ComponentDecorator extends TypeDecorator {
   /**
@@ -59,6 +63,8 @@ export interface ComponentDecorator extends TypeDecorator {
  * Interface for the {@link ViewMetadata} decorator function.
  *
  * See {@link ViewFactory}.
+ *
+ * @experimental
  */
 export interface ViewDecorator extends TypeDecorator {
   /**
@@ -107,6 +113,8 @@ export interface ViewDecorator extends TypeDecorator {
  *   new ng.Directive({...})
  * ]
  * ```
+ *
+ * @stable
  */
 export interface DirectiveMetadataFactory {
   (obj: {
@@ -163,6 +171,8 @@ export interface DirectiveMetadataFactory {
  *   new ng.Component({...})
  * ]
  * ```
+ *
+ * @stable
  */
 export interface ComponentMetadataFactory {
   (obj: {
@@ -256,6 +266,8 @@ export interface ComponentMetadataFactory {
  *   new ng.View({...})
  * ]
  * ```
+ *
+ * @experimental You should most likely use ComponentMetadataFactory instead
  */
 export interface ViewMetadataFactory {
   (obj: {
@@ -315,6 +327,8 @@ export interface ViewMetadataFactory {
  *   [new ng.Attribute('title')]
  * ]
  * ```
+ *
+ * @stable
  */
 export interface AttributeMetadataFactory {
   (name: string): TypeDecorator;