fix: 重新合并 doc-viewer 中的翻译代码（未包含标题翻译）

aio/src/app/layout/doc-viewer/doc-viewer.component.ts

@@ -1,4 +1,5 @@
 import { Component, ComponentRef, DoCheck, ElementRef, EventEmitter, Input, OnDestroy, Output } from '@angular/core';
+import { HostListener } from '@angular/core';
 import { Title, Meta } from '@angular/platform-browser';
 
 import { Observable } from 'rxjs/Observable';
@@ -78,6 +79,7 @@ export class DocViewerComponent implements DoCheck, OnDestroy {
     this.hostElement = elementRef.nativeElement;
     // Security: the initialDocViewerContent comes from the prerendered DOM and is considered to be secure
     this.hostElement.innerHTML = initialDocViewerContent;
+    swapOriginAndResult(this.hostElement);
 
     if (this.hostElement.firstElementChild) {
       this.currViewContainer = this.hostElement.firstElementChild as HTMLElement;
@@ -148,6 +150,7 @@ export class DocViewerComponent implements DoCheck, OnDestroy {
     // Security: `doc.contents` is always authored by the documentation team
     //           and is considered to be safe.
       .do(() => this.nextViewContainer.innerHTML = doc.contents || '')
+      .do(() => swapOriginAndResult(this.nextViewContainer))
       .do(() => addTitleAndToc = this.prepareTitleAndToc(this.nextViewContainer, doc.id))
       .switchMap(() => this.embedComponentsService.embedInto(this.nextViewContainer))
       .do(() => this.docReady.emit())
@@ -252,4 +255,40 @@ export class DocViewerComponent implements DoCheck, OnDestroy {
         this.nextViewContainer.innerHTML = '';  // Empty to release memory.
       });
   }
+
+  @HostListener('click', ['$event'])
+  toggleTranslationOrigin($event: MouseEvent): void {
+    const element = findTranslationResult($event.target as Element);
+    if (element && element.hasAttribute('translation-result')) {
+      const origin = element.nextElementSibling;
+      if (!origin || origin.hasAttribute('translation-result') || origin.tagName !== element.tagName) {
+        return;
+      }
+
+      if (origin.getAttribute('translation-origin') === 'on') {
+        origin.setAttribute('translation-origin', 'off');
+      } else {
+        origin.setAttribute('translation-origin', 'on');
+      }
+    }
+  }
+
+}
+
+function findTranslationResult(element: Element | null): Element | null {
+  while (element && !element.hasAttribute('translation-result')) {
+    element = element.parentElement;
+  }
+  return element;
+}
+
+function swapOriginAndResult(root: Element): void {
+  const results = root.querySelectorAll('[translation-result]');
+  for (let i = 0; i < results.length; ++i) {
+    const result = results.item(i);
+    const origin = result.previousElementSibling;
+    if (origin && origin.hasAttribute('translation-origin') && origin.parentElement) {
+      origin.parentElement.insertBefore(result, origin);
+    }
+  }
 }