adjust build for firefox 68 ESR compatibility

gulpfile.mjs

@@ -79,7 +79,7 @@ const config = JSON.parse(fs.readFileSync(CONFIG_FILE).toString());
 const ENV_TARGETS = [
   "last 2 versions",
   "Chrome >= 92",
-  "Firefox ESR",
+  "Firefox >= 68",
   "Safari >= 15.4",
   "Node >= 18",
   "> 1%",

package.json

@@ -44,6 +44,7 @@
     "postcss-nesting": "^12.0.1",
     "prettier": "^3.0.3",
     "puppeteer": "^21.2.1",
+    "resize-observer-polyfill": "^1.5.1",
     "rimraf": "^3.0.2",
     "streamqueue": "^1.1.2",
     "stylelint": "^15.10.3",

src/display/editor/ink.js

@@ -22,6 +22,7 @@ import { AnnotationEditor } from "./editor.js";
 import { InkAnnotationElement } from "../annotation_layer.js";
 import { noContextMenu } from "../display_utils.js";
 import { opacityToHex } from "./tools.js";
+import ResizeObserver from 'resize-observer-polyfill';
 
 /**
  * Basic draw editor in order to generate an Ink annotation.

src/display/editor/stamp.js

@@ -17,6 +17,7 @@ import { AnnotationEditorType, shadow } from "../../shared/util.js";
 import { AnnotationEditor } from "./editor.js";
 import { PixelsPerInch } from "../display_utils.js";
 import { StampAnnotationElement } from "../annotation_layer.js";
+import ResizeObserver from 'resize-observer-polyfill';
 
 /**
  * Basic text editor in order to create a FreeTex annotation.

web/pdf_viewer.js

@@ -12,6 +12,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+import ResizeObserver from 'resize-observer-polyfill';
 
 /** @typedef {import("../src/display/api").PDFDocumentProxy} PDFDocumentProxy */
 /** @typedef {import("../src/display/api").PDFPageProxy} PDFPageProxy */