perf(compiler): make the creation of ts.Program faster. (#19275)

We now create 2 programs with exactly the same fileNames and
exactly the same `import` / `export` declarations,
allowing TS to reuse the structure of first program
completely. When passing in an oldProgram and the files didn’t change,
TS can also reuse the old program completely.

This is possible buy adding generated files to TS
in `host.geSourceFile` via `ts.SourceFile.referencedFiles`.

This commit also:
- has a minor side effect on how we generate shared stylesheets:
  - previously every import in a stylesheet would generate a new
    `.ngstyles.ts` file.
  - now, we only generate 1 `.ngstyles.ts` file per entry in `@Component.styleUrls`.
  This was required as we need to be able to determine the program files
  without loading the resources (which can be async).
- makes all angular related methods in `CompilerHost`
  optional, allowing to just use a regular `ts.CompilerHost` as `CompilerHost`.
- simplifies the logic around `Compiler.analyzeNgModules` by introducing `NgAnalyzedFile`.

Perf impact: 1.5s improvement in compiling angular io
PR Close #19275

packages/compiler/src/metadata_resolver.ts

@@ -12,14 +12,16 @@ import {assertArrayOfStrings, assertInterpolationSymbols} from './assertions';
 import * as cpl from './compile_metadata';
 import {CompileReflector} from './compile_reflector';
 import {CompilerConfig} from './config';
-import {ChangeDetectionStrategy, Component, Directive, ModuleWithProviders, Provider, Query, SchemaMetadata, Type, createAttribute, createComponent, createHost, createInject, createInjectable, createInjectionToken, createOptional, createSelf, createSkipSelf} from './core';
+import {ChangeDetectionStrategy, Component, Directive, ModuleWithProviders, Provider, Query, SchemaMetadata, Type, ViewEncapsulation, createAttribute, createComponent, createHost, createInject, createInjectable, createInjectionToken, createOptional, createSelf, createSkipSelf} from './core';
 import {DirectiveNormalizer} from './directive_normalizer';
 import {DirectiveResolver} from './directive_resolver';
 import {Identifiers} from './identifiers';
 import {getAllLifecycleHooks} from './lifecycle_reflector';
+import {HtmlParser} from './ml_parser/html_parser';
 import {NgModuleResolver} from './ng_module_resolver';
 import {PipeResolver} from './pipe_resolver';
 import {ElementSchemaRegistry} from './schema/element_schema_registry';
+import {CssSelector} from './selector';
 import {SummaryResolver} from './summary_resolver';
 import {Console, SyncAsync, ValueTransformer, isPromise, noUndefined, resolveForwardRef, stringify, syntaxError, visitValue} from './util';
 
@@ -44,9 +46,9 @@ export class CompileMetadataResolver {
   private _ngModuleOfTypes = new Map<Type, Type>();
 
   constructor(
-      private _config: CompilerConfig, private _ngModuleResolver: NgModuleResolver,
-      private _directiveResolver: DirectiveResolver, private _pipeResolver: PipeResolver,
-      private _summaryResolver: SummaryResolver<any>,
+      private _config: CompilerConfig, private _htmlParser: HtmlParser,
+      private _ngModuleResolver: NgModuleResolver, private _directiveResolver: DirectiveResolver,
+      private _pipeResolver: PipeResolver, private _summaryResolver: SummaryResolver<any>,
       private _schemaRegistry: ElementSchemaRegistry,
       private _directiveNormalizer: DirectiveNormalizer, private _console: Console,
       private _staticSymbolCache: StaticSymbolCache, private _reflector: CompileReflector,
@@ -167,6 +169,54 @@ export class CompileMetadataResolver {
     return typeSummary && typeSummary.summaryKind === kind ? typeSummary : null;
   }
 
+  getHostComponentMetadata(
+      compMeta: cpl.CompileDirectiveMetadata,
+      hostViewType?: StaticSymbol|cpl.ProxyClass): cpl.CompileDirectiveMetadata {
+    const hostType = this.getHostComponentType(compMeta.type.reference);
+    if (!hostViewType) {
+      hostViewType = this.getHostComponentViewClass(hostType);
+    }
+    // Note: ! is ok here as this method should only be called with normalized directive
+    // metadata, which always fills in the selector.
+    const template = CssSelector.parse(compMeta.selector !)[0].getMatchingElementTemplate();
+    const templateUrl = '';
+    const htmlAst = this._htmlParser.parse(template, templateUrl);
+    return cpl.CompileDirectiveMetadata.create({
+      isHost: true,
+      type: {reference: hostType, diDeps: [], lifecycleHooks: []},
+      template: new cpl.CompileTemplateMetadata({
+        encapsulation: ViewEncapsulation.None,
+        template,
+        templateUrl,
+        htmlAst,
+        styles: [],
+        styleUrls: [],
+        ngContentSelectors: [],
+        animations: [],
+        isInline: true,
+        externalStylesheets: [],
+        interpolation: null,
+        preserveWhitespaces: false,
+      }),
+      exportAs: null,
+      changeDetection: ChangeDetectionStrategy.Default,
+      inputs: [],
+      outputs: [],
+      host: {},
+      isComponent: true,
+      selector: '*',
+      providers: [],
+      viewProviders: [],
+      queries: [],
+      viewQueries: [],
+      componentViewType: hostViewType,
+      rendererType:
+          {id: '__Host__', encapsulation: ViewEncapsulation.None, styles: [], data: {}} as object,
+      entryComponents: [],
+      componentFactory: null
+    });
+  }
+
   loadDirectiveMetadata(ngModuleType: any, directiveType: any, isSync: boolean): SyncAsync<null> {
     if (this._directiveCache.has(directiveType)) {
       return null;