Revert failed merge "Improvements for Content Copy (go-gitea#21842)"

This reverts commit f3b3149.

web_src/js/utils.js

@@ -133,51 +133,3 @@ export function convertImage(blob, mime) {
     }
   });
 }
-
-// convert a Blob to a DataURI
-export function blobToDataURI(blob) {
-  return new Promise((resolve, reject) => {
-    try {
-      const reader = new FileReader();
-      reader.addEventListener('load', (e) => {
-        resolve(e.target.result);
-      });
-      reader.addEventListener('error', () => {
-        reject(new Error('FileReader failed'));
-      });
-      reader.readAsDataURL(blob);
-    } catch (err) {
-      reject(err);
-    }
-  });
-}
-
-// convert image Blob to another mime-type format.
-export function convertImage(blob, mime) {
-  return new Promise(async (resolve, reject) => {
-    try {
-      const img = new Image();
-      const canvas = document.createElement('canvas');
-      img.addEventListener('load', () => {
-        try {
-          canvas.width = img.naturalWidth;
-          canvas.height = img.naturalHeight;
-          const context = canvas.getContext('2d');
-          context.drawImage(img, 0, 0);
-          canvas.toBlob((blob) => {
-            if (!(blob instanceof Blob)) return reject(new Error('imageBlobToPng failed'));
-            resolve(blob);
-          }, mime);
-        } catch (err) {
-          reject(err);
-        }
-      });
-      img.addEventListener('error', () => {
-        reject(new Error('imageBlobToPng failed'));
-      });
-      img.src = await blobToDataURI(blob);
-    } catch (err) {
-      reject(err);
-    }
-  });
-}