fix(core): allow tree shaking of component factories and styles (#15214)

Closure compiler is very sensitive to top level function calls.
This commit makes the function calls `createComponentFactory`
and `createRendererTypeV2` logic-less.

Fixes #15181

PR Close #15214

packages/core/src/view/element.ts

@@ -6,11 +6,12 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
+import {ViewEncapsulation} from '../metadata/view';
 import {Renderer2, RendererType2} from '../render/api';
 import {SecurityContext} from '../security';
 
 import {BindingDef, BindingType, DebugContext, DisposableFn, ElementData, ElementHandleEventFn, NodeData, NodeDef, NodeFlags, OutputDef, OutputType, QueryValueType, Services, ViewData, ViewDefinition, ViewDefinitionFactory, ViewFlags, asElementData, asProviderData} from './types';
-import {NOOP, checkAndUpdateBinding, dispatchEvent, elementEventFullName, filterQueryId, getParentRenderElement, resolveViewDefinition, splitMatchedQueriesDsl, splitNamespace} from './util';
+import {NOOP, checkAndUpdateBinding, dispatchEvent, elementEventFullName, filterQueryId, getParentRenderElement, resolveRendererType2, resolveViewDefinition, splitMatchedQueriesDsl, splitNamespace} from './util';
 
 export function anchorDef(
     flags: NodeFlags, matchedQueriesDsl: [string | number, QueryValueType][],
@@ -112,11 +113,7 @@ export function elementDef(
     const [ns, name] = splitNamespace(namespaceAndName);
     return [ns, name, value];
   });
-  // This is needed as the jit compiler always uses an empty hash as default RendererType2,
-  // which is not filled for host views.
-  if (componentRendererType && componentRendererType.encapsulation == null) {
-    componentRendererType = null;
-  }
+  componentRendererType = resolveRendererType2(componentRendererType);
   if (componentView) {
     flags |= NodeFlags.ComponentView;
   }

packages/core/src/view/refs.ts

@@ -25,22 +25,14 @@ import {attachEmbeddedView, detachEmbeddedView, moveEmbeddedView, renderDetachVi
 
 const EMPTY_CONTEXT = new Object();
 
+// Attention: this function is called as top level function.
+// Putting any logic in here will destroy closure tree shaking!
 export function createComponentFactory(
     selector: string, componentType: Type<any>, viewDefFactory: ViewDefinitionFactory,
     inputs: {[propName: string]: string}, outputs: {[propName: string]: string},
     ngContentSelectors: string[]): ComponentFactory<any> {
-  const inputsArr: {propName: string, templateName: string}[] = [];
-  for (let propName in inputs) {
-    const templateName = inputs[propName];
-    inputsArr.push({propName, templateName});
-  }
-  const outputsArr: {propName: string, templateName: string}[] = [];
-  for (let propName in outputs) {
-    const templateName = outputs[propName];
-    outputsArr.push({propName, templateName});
-  }
   return new ComponentFactory_(
-      selector, componentType, viewDefFactory, inputsArr, outputsArr, ngContentSelectors);
+      selector, componentType, viewDefFactory, inputs, outputs, ngContentSelectors);
 }
 
 export function getComponentViewDefinitionFactory(componentFactory: ComponentFactory<any>):
@@ -56,14 +48,32 @@ class ComponentFactory_ extends ComponentFactory<any> {
 
   constructor(
       public selector: string, public componentType: Type<any>,
-      viewDefFactory: ViewDefinitionFactory,
-      public inputs: {propName: string, templateName: string}[],
-      public outputs: {propName: string, templateName: string}[],
-      public ngContentSelectors: string[]) {
+      viewDefFactory: ViewDefinitionFactory, private _inputs: {[propName: string]: string},
+      private _outputs: {[propName: string]: string}, public ngContentSelectors: string[]) {
+    // Attention: this ctor is called as top level function.
+    // Putting any logic in here will destroy closure tree shaking!
     super();
     this.viewDefFactory = viewDefFactory;
   }
 
+  get inputs() {
+    const inputsArr: {propName: string, templateName: string}[] = [];
+    for (let propName in this._inputs) {
+      const templateName = this._inputs[propName];
+      inputsArr.push({propName, templateName});
+    }
+    return inputsArr;
+  }
+
+  get outputs() {
+    const outputsArr: {propName: string, templateName: string}[] = [];
+    for (let propName in this._outputs) {
+      const templateName = this._outputs[propName];
+      outputsArr.push({propName, templateName});
+    }
+    return outputsArr;
+  }
+
   /**
    * Creates a new component.
    */

packages/core/src/view/util.ts

@@ -42,21 +42,42 @@ export function unwrapValue(value: any): any {
   return value;
 }
 
-let _renderCompCount = 0;
+const UNDEFINED_RENDERER_TYPE_ID = '$$undefined';
+const EMPTY_RENDERER_TYPE_ID = '$$empty';
 
+// Attention: this function is called as top level function.
+// Putting any logic in here will destroy closure tree shaking!
 export function createRendererType2(values: {
   styles: (string | any[])[],
   encapsulation: ViewEncapsulation,
   data: {[kind: string]: any[]}
 }): RendererType2 {
-  const isFilled = values && (values.encapsulation !== ViewEncapsulation.None ||
-                              values.styles.length || Object.keys(values.data).length);
-  if (isFilled) {
-    const id = `c${_renderCompCount++}`;
-    return {id: id, styles: values.styles, encapsulation: values.encapsulation, data: values.data};
-  } else {
-    return null;
+  return {
+    id: UNDEFINED_RENDERER_TYPE_ID,
+    styles: values.styles,
+    encapsulation: values.encapsulation,
+    data: values.data
+  };
+}
+
+let _renderCompCount = 0;
+
+export function resolveRendererType2(type: RendererType2): RendererType2 {
+  if (type && type.id === UNDEFINED_RENDERER_TYPE_ID) {
+    // first time we see this RendererType2. Initialize it...
+    const isFilled =
+        ((type.encapsulation != null && type.encapsulation !== ViewEncapsulation.None) ||
+         type.styles.length || Object.keys(type.data).length);
+    if (isFilled) {
+      type.id = `c${_renderCompCount++}`;
+    } else {
+      type.id = EMPTY_RENDERER_TYPE_ID;
+    }
   }
+  if (type && type.id === EMPTY_RENDERER_TYPE_ID) {
+    type = null;
+  }
+  return type;
 }
 
 export function checkBinding(