[api-major] Remove the enhanceTextSelection functionality (PR 15145 follow-up)

For the `gulp mozcentral` command, this reduces the size of the *built* `pdf.js` file by `> 10` kB.

extensions/chromium/options/migration.js

@@ -109,17 +109,10 @@ limitations under the License.
         }
         // Migration code for https://github.com/mozilla/pdf.js/pull/9479.
         if (typeof items.disableTextLayer === "boolean") {
-          var textLayerMode = 1;
           if (items.disableTextLayer) {
-            textLayerMode = 0;
-          } else if (items.enhanceTextSelection) {
-            textLayerMode = 2;
-          }
-          if (textLayerMode !== 1) {
-            // Overwrite if computed textLayerMode is not the default value (1).
             storageSync.set(
               {
-                textLayerMode,
+                textLayerMode: 0,
               },
               function () {
                 if (!chrome.runtime.lastError) {

extensions/chromium/options/options.html

@@ -126,7 +126,6 @@ body {
     <select>
       <option value="0">Disable text selection</option>
       <option value="1">Enable text selection</option>
-      <option value="2">Enable enhanced mode (experimental)</option>
     </select>
   </label>
 </div>

extensions/chromium/preferences_schema.json

@@ -102,19 +102,13 @@
       "type": "boolean",
       "default": false
     },
-    "enhanceTextSelection": {
-      "description": "DEPRECATED. Set textLayerMode to 2 to use the enhanced text selection layer by default.",
-      "type": "boolean",
-      "default": false
-    },
     "textLayerMode": {
       "title": "Text layer mode",
-      "description": "Controls if the text layer is enabled, and the selection mode that is used.\n 0 = Disabled.\n 1 = Enabled.\n 2 = (Experimental) Enabled, with enhanced text selection.",
+      "description": "Controls if the text layer is enabled, and the selection mode that is used.\n 0 = Disabled.\n 1 = Enabled.",
       "type": "integer",
       "enum": [
         0,
-        1,
+        1
-        2
       ],
       "default": 1
     },

src/display/text_layer.js

@@ -18,7 +18,6 @@ import {
   createPromiseCapability,
   Util,
 } from "../shared/util.js";
-import { deprecated } from "./display_utils.js";
 
 /**
  * Text layer render parameters.
@@ -40,15 +39,12 @@ import { deprecated } from "./display_utils.js";
  *   This is output and shall initially be set to an empty array.
  * @property {number} [timeout] - Delay in milliseconds before rendering of the
  *   text runs occurs.
- * @property {boolean} [enhanceTextSelection] - Whether to turn on the text
- *   selection enhancement.
  */
 
 const MAX_TEXT_DIVS_TO_RENDER = 100000;
 const DEFAULT_FONT_SIZE = 30;
 const DEFAULT_FONT_ASCENT = 0.8;
 const ascentCache = new Map();
-const AllWhitespaceRegexp = /^\s+$/g;
 
 function getAscent(fontFamily, ctx) {
   const cachedAscent = ascentCache.get(fontFamily);
@@ -120,28 +116,13 @@ function getAscent(fontFamily, ctx) {
 function appendText(task, geom, styles, ctx) {
   // Initialize all used properties to keep the caches monomorphic.
   const textDiv = document.createElement("span");
-  const textDivProperties = task._enhanceTextSelection
+  const textDivProperties = {
-    ? {
-        angle: 0,
-        canvasWidth: 0,
-        hasText: geom.str !== "",
-        hasEOL: geom.hasEOL,
-        originalTransform: null,
-        paddingBottom: 0,
-        paddingLeft: 0,
-        paddingRight: 0,
-        paddingTop: 0,
-        scale: 1,
-        fontSize: 0,
-      }
-    : {
     angle: 0,
     canvasWidth: 0,
     hasText: geom.str !== "",
     hasEOL: geom.hasEOL,
     fontSize: 0,
   };
-
   task._textDivs.push(textDiv);
 
   const tx = Util.transform(task._viewport.transform, geom.transform);
@@ -189,10 +170,7 @@ function appendText(task, geom, styles, ctx) {
   // little effect on text highlighting. This makes scrolling on docs with
   // lots of such divs a lot faster.
   let shouldScaleText = false;
-  if (
+  if (geom.str.length > 1) {
-    geom.str.length > 1 ||
-    (task._enhanceTextSelection && AllWhitespaceRegexp.test(geom.str))
-  ) {
     shouldScaleText = true;
   } else if (geom.str !== " " && geom.transform[0] !== geom.transform[3]) {
     const absScaleX = Math.abs(geom.transform[0]),
@@ -217,36 +195,6 @@ function appendText(task, geom, styles, ctx) {
   if (task._textContentStream) {
     task._layoutText(textDiv);
   }
-
-  if (task._enhanceTextSelection && textDivProperties.hasText) {
-    let angleCos = 1,
-      angleSin = 0;
-    if (angle !== 0) {