Remove the CustomStyle class

It is only used in a few places to handle prefixing style properties if
necessary. However, we used it only for `transform`, `transformOrigin`
and `borderRadius`, which according to Can I Use are supported natively
(unprefixed) in the browsers that PDF.js 2.0 supports. Therefore, we can
remove this class, which should help performance too since this avoids
extra function calls in parts of the code that are called often.

src/display/annotation_layer.js

@@ -14,8 +14,8 @@
  */
 
 import {
-  addLinkAttributes, CustomStyle, DOMSVGFactory, getDefaultSetting,
-  getFilenameFromUrl, LinkTarget
+  addLinkAttributes, DOMSVGFactory, getDefaultSetting, getFilenameFromUrl,
+  LinkTarget
 } from './dom_utils';
 import {
   AnnotationBorderStyleType, AnnotationType, stringToPDFString, unreachable,
@@ -153,10 +153,8 @@ class AnnotationElement {
       page.view[3] - data.rect[3] + page.view[1]
     ]);
 
-    CustomStyle.setProp('transform', container,
-                        'matrix(' + viewport.transform.join(',') + ')');
-    CustomStyle.setProp('transformOrigin', container,
-                        -rect[0] + 'px ' + -rect[1] + 'px');
+    container.style.transform = 'matrix(' + viewport.transform.join(',') + ')';
+    container.style.transformOrigin = -rect[0] + 'px ' + -rect[1] + 'px';
 
     if (!ignoreBorder && data.borderStyle.width > 0) {
       container.style.borderWidth = data.borderStyle.width + 'px';
@@ -172,7 +170,7 @@ class AnnotationElement {
       let verticalRadius = data.borderStyle.verticalCornerRadius;
       if (horizontalRadius > 0 || verticalRadius > 0) {
         let radius = horizontalRadius + 'px / ' + verticalRadius + 'px';
-        CustomStyle.setProp('borderRadius', container, radius);
+        container.style.borderRadius = radius;
       }
 
       switch (data.borderStyle.style) {
@@ -652,9 +650,8 @@ class PopupAnnotationElement extends AnnotationElement {
     // PDF viewers ignore a popup annotation's rectangle.
     let parentLeft = parseFloat(parentElement.style.left);
     let parentWidth = parseFloat(parentElement.style.width);
-    CustomStyle.setProp('transformOrigin', this.container,
-                        -(parentLeft + parentWidth) + 'px -' +
-                        parentElement.style.top);
+    this.container.style.transformOrigin =
+      -(parentLeft + parentWidth) + 'px -' + parentElement.style.top;
     this.container.style.left = (parentLeft + parentWidth) + 'px';
 
     this.container.appendChild(popup.render());
@@ -1235,8 +1232,8 @@ class AnnotationLayer {
       let element = parameters.div.querySelector(
         '[data-annotation-id="' + data.id + '"]');
       if (element) {
-        CustomStyle.setProp('transform', element,
-          'matrix(' + parameters.viewport.transform.join(',') + ')');
+        element.style.transform =
+          'matrix(' + parameters.viewport.transform.join(',') + ')';
       }
     }
     parameters.div.removeAttribute('hidden');

src/display/dom_utils.js

@@ -261,60 +261,6 @@ class SimpleXMLParser {
   }
 }
 
-/**
- * Optimised CSS custom property getter/setter.
- * @class
- */
-var CustomStyle = (function CustomStyleClosure() {
-
-  // As noted on: http://www.zachstronaut.com/posts/2009/02/17/
-  //              animate-css-transforms-firefox-webkit.html
-  // in some versions of IE9 it is critical that ms appear in this list
-  // before Moz
-  var prefixes = ['ms', 'Moz', 'Webkit', 'O'];
-  var _cache = Object.create(null);
-
-  function CustomStyle() {}
-
-  CustomStyle.getProp = function get(propName, element) {
-    // check cache only when no element is given
-    if (arguments.length === 1 && typeof _cache[propName] === 'string') {
-      return _cache[propName];
-    }
-
-    element = element || document.documentElement;
-    var style = element.style, prefixed, uPropName;
-
-    // test standard property first
-    if (typeof style[propName] === 'string') {
-      return (_cache[propName] = propName);
-    }
-
-    // capitalize
-    uPropName = propName.charAt(0).toUpperCase() + propName.slice(1);
-
-    // test vendor specific properties
-    for (var i = 0, l = prefixes.length; i < l; i++) {
-      prefixed = prefixes[i] + uPropName;
-      if (typeof style[prefixed] === 'string') {
-        return (_cache[propName] = prefixed);
-      }
-    }
-
-    // If all fails then set to undefined.
-    return (_cache[propName] = 'undefined');
-  };
-
-  CustomStyle.setProp = function set(propName, element, str) {
-    var prop = this.getProp(propName);
-    if (prop !== 'undefined') {
-      element.style[prop] = str;
-    }
-  };
-
-  return CustomStyle;
-})();
-
 var RenderingCancelledException = (function RenderingCancelledException() {
   function RenderingCancelledException(msg, type) {
     this.message = msg;
@@ -543,7 +489,6 @@ class DummyStatTimer {
 }
 
 export {
-  CustomStyle,
   RenderingCancelledException,
   addLinkAttributes,
   isExternalLinkTargetSet,

src/display/global.js

@@ -14,7 +14,7 @@
  */
 
 import {
-  addLinkAttributes, CustomStyle, DEFAULT_LINK_REL, getFilenameFromUrl,
+  addLinkAttributes, DEFAULT_LINK_REL, getFilenameFromUrl,
   isExternalLinkTargetSet, isValidUrl, LinkTarget
 } from './dom_utils';
 import {
@@ -243,7 +243,6 @@ PDFJS.LoopbackPort = LoopbackPort;
 PDFJS.PDFDataRangeTransport = PDFDataRangeTransport;
 PDFJS.PDFWorker = PDFWorker;
 
-PDFJS.CustomStyle = CustomStyle;
 PDFJS.LinkTarget = LinkTarget;
 PDFJS.addLinkAttributes = addLinkAttributes;
 PDFJS.getFilenameFromUrl = getFilenameFromUrl;

src/display/text_layer.js

@@ -14,7 +14,7 @@
  */
 
 import { AbortException, createPromiseCapability, Util } from '../shared/util';
-import { CustomStyle, getDefaultSetting } from './dom_utils';
+import { getDefaultSetting } from './dom_utils';
 
 /**
  * Text layer render parameters.
@@ -547,7 +547,7 @@ var renderTextLayer = (function renderTextLayerClosure() {
       }
       if (transform !== '') {
         textDivProperties.originalTransform = transform;
-        CustomStyle.setProp('transform', textDiv, transform);
+        textDiv.style.transform = transform;
       }
       this._textDivProperties.set(textDiv, textDivProperties);
       textLayerFrag.appendChild(textDiv);
@@ -653,12 +653,11 @@ var renderTextLayer = (function renderTextLayerClosure() {
             div.setAttribute('style', divProperties.style + padding);
           }
           if (transform !== '') {
-            CustomStyle.setProp('transform', div, transform);
+            div.style.transform = transform;
           }
         } else {
           div.style.padding = 0;
-          CustomStyle.setProp('transform', div,
-                              divProperties.originalTransform || '');
+          div.style.transform = divProperties.originalTransform || '';
         }
       }
     },

src/pdf.js

@@ -53,7 +53,6 @@ exports.PDFDataRangeTransport = pdfjsDisplayAPI.PDFDataRangeTransport;
 exports.PDFWorker = pdfjsDisplayAPI.PDFWorker;
 exports.renderTextLayer = pdfjsDisplayTextLayer.renderTextLayer;
 exports.AnnotationLayer = pdfjsDisplayAnnotationLayer.AnnotationLayer;
-exports.CustomStyle = pdfjsDisplayDOMUtils.CustomStyle;
 exports.createPromiseCapability = pdfjsSharedUtil.createPromiseCapability;
 exports.PasswordResponses = pdfjsSharedUtil.PasswordResponses;
 exports.InvalidPDFException = pdfjsSharedUtil.InvalidPDFException;

web/pdf_page_view.js

@@ -18,8 +18,7 @@ import {
   RendererType, roundToDivide
 } from './ui_utils';
 import {
-  createPromiseCapability, CustomStyle, PDFJS, RenderingCancelledException,
-  SVGGraphics
+  createPromiseCapability, PDFJS, RenderingCancelledException, SVGGraphics
 } from 'pdfjs-lib';
 import { getGlobalEventBus } from './dom_events';
 import { RenderingStates } from './pdf_rendering_queue';
@@ -280,7 +279,7 @@ class PDFPageView {
     }
     let cssTransform = 'rotate(' + relativeRotation + 'deg) ' +
       'scale(' + scaleX + ',' + scaleY + ')';
-    CustomStyle.setProp('transform', target, cssTransform);
+    target.style.transform = cssTransform;
 
     if (this.textLayer) {
       // Rotating the text layer is more complicated since the divs inside the
@@ -317,11 +316,12 @@ class PDFPageView {
           console.error('Bad rotation value.');
           break;
       }
-      CustomStyle.setProp('transform', textLayerDiv,
-          'rotate(' + textAbsRotation + 'deg) ' +
-          'scale(' + scale + ', ' + scale + ') ' +
-          'translate(' + transX + ', ' + transY + ')');
-      CustomStyle.setProp('transformOrigin', textLayerDiv, '0% 0%');
+
+      textLayerDiv.style.transform =
+        'rotate(' + textAbsRotation + 'deg) ' +
+        'scale(' + scale + ', ' + scale + ') ' +
+        'translate(' + transX + ', ' + transY + ')';
+      textLayerDiv.style.transformOrigin = '0% 0%';
     }
 
     if (redrawAnnotations && this.annotationLayer) {