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diff --git a/dom/manifest/ImageObjectProcessor.sys.mjs b/dom/manifest/ImageObjectProcessor.sys.mjs
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+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+/*
+ * ImageObjectProcessor
+ * Implementation of Image Object processing algorithms from:
+ * http://www.w3.org/TR/appmanifest/#image-object-and-its-members
+ *
+ * This is intended to be used in conjunction with ManifestProcessor.jsm
+ *
+ * Creates an object to process Image Objects as defined by the
+ * W3C specification. This is used to process things like the
+ * icon member and the splash_screen member.
+ *
+ * Usage:
+ *
+ *   .process(aManifest, aBaseURL, aMemberName);
+ *
+ */
+
+export function ImageObjectProcessor(aErrors, aExtractor, aBundle) {
+  this.errors = aErrors;
+  this.extractor = aExtractor;
+  this.domBundle = aBundle;
+}
+
+const iconPurposes = Object.freeze(["any", "maskable", "monochrome"]);
+
+// Static getters
+Object.defineProperties(ImageObjectProcessor, {
+  decimals: {
+    get() {
+      return /^\d+$/;
+    },
+  },
+  anyRegEx: {
+    get() {
+      return new RegExp("any", "i");
+    },
+  },
+});
+
+ImageObjectProcessor.prototype.process = function (
+  aManifest,
+  aBaseURL,
+  aMemberName
+) {
+  const spec = {
+    objectName: "manifest",
+    object: aManifest,
+    property: aMemberName,
+    expectedType: "array",
+    trim: false,
+  };
+  const { domBundle, extractor, errors } = this;
+  const images = [];
+  const value = extractor.extractValue(spec);
+  if (Array.isArray(value)) {
+    value
+      .map(toImageObject)
+      // Filter out images that resulted in "failure", per spec.
+      .filter(image => image)
+      .forEach(image => images.push(image));
+  }
+  return images;
+
+  function toImageObject(aImageSpec, index) {
+    let img; // if "failure" happens below, we return undefined.
+    try {
+      // can throw
+      const src = processSrcMember(aImageSpec, aBaseURL, index);
+      // can throw
+      const purpose = processPurposeMember(aImageSpec, index);
+      const type = processTypeMember(aImageSpec);
+      const sizes = processSizesMember(aImageSpec);
+      img = {
+        src,
+        purpose,
+        type,
+        sizes,
+      };
+    } catch (err) {
+      /* Errors are collected by each process* function */
+    }
+    return img;
+  }
+
+  function processPurposeMember(aImage, index) {
+    const spec = {
+      objectName: "image",
+      object: aImage,
+      property: "purpose",
+      expectedType: "string",
+      trim: true,
+      throwTypeError: true,
+    };
+
+    // Type errors are treated at "any"...
+    let value;
+    try {
+      value = extractor.extractValue(spec);
+    } catch (err) {
+      return ["any"];
+    }
+
+    // Was only whitespace...
+    if (!value) {
+      return ["any"];
+    }
+
+    const keywords = value.split(/\s+/);
+
+    // Emtpy is treated as "any"...
+    if (keywords.length === 0) {
+      return ["any"];
+    }
+
+    // We iterate over keywords and classify them into:
+    const purposes = new Set();
+    const unknownPurposes = new Set();
+    const repeatedPurposes = new Set();
+
+    for (const keyword of keywords) {
+      const canonicalKeyword = keyword.toLowerCase();
+
+      if (purposes.has(canonicalKeyword)) {
+        repeatedPurposes.add(keyword);
+        continue;
+      }
+
+      iconPurposes.includes(canonicalKeyword)
+        ? purposes.add(canonicalKeyword)
+        : unknownPurposes.add(keyword);
+    }
+
+    // Tell developer about unknown purposes...
+    if (unknownPurposes.size) {
+      const warn = domBundle.formatStringFromName(
+        "ManifestImageUnsupportedPurposes",
+        [aMemberName, index, [...unknownPurposes].join(" ")]
+      );
+      errors.push({ warn });
+    }
+
+    // Tell developer about repeated purposes...
+    if (repeatedPurposes.size) {
+      const warn = domBundle.formatStringFromName(
+        "ManifestImageRepeatedPurposes",
+        [aMemberName, index, [...repeatedPurposes].join(" ")]
+      );
+      errors.push({ warn });
+    }
+
+    if (purposes.size === 0) {
+      const warn = domBundle.formatStringFromName("ManifestImageUnusable", [
+        aMemberName,
+        index,
+      ]);
+      errors.push({ warn });
+      throw new TypeError(warn);
+    }
+
+    return [...purposes];
+  }
+
+  function processTypeMember(aImage) {
+    const charset = {};
+    const hadCharset = {};
+    const spec = {
+      objectName: "image",
+      object: aImage,
+      property: "type",
+      expectedType: "string",
+      trim: true,
+    };
+    let value = extractor.extractValue(spec);
+    if (value) {
+      value = Services.io.parseRequestContentType(value, charset, hadCharset);
+    }
+    return value || undefined;
+  }
+
+  function processSrcMember(aImage, aBaseURL, index) {
+    const spec = {
+      objectName: aMemberName,
+      object: aImage,
+      property: "src",
+      expectedType: "string",
+      trim: false,
+      throwTypeError: true,
+    };
+    const value = extractor.extractValue(spec);
+    let url;
+    if (typeof value === "undefined" || value === "") {
+      // We throw here as the value is unusable,
+      // but it's not an developer error.
+      throw new TypeError();
+    }
+    if (value && value.length) {
+      try {
+        url = new URL(value, aBaseURL).href;
+      } catch (e) {
+        const warn = domBundle.formatStringFromName(
+          "ManifestImageURLIsInvalid",
+          [aMemberName, index, "src", value]
+        );
+        errors.push({ warn });
+        throw e;
+      }
+    }
+    return url;
+  }
+
+  function processSizesMember(aImage) {
+    const sizes = new Set();
+    const spec = {
+      objectName: "image",
+      object: aImage,
+      property: "sizes",
+      expectedType: "string",
+      trim: true,
+    };
+    const value = extractor.extractValue(spec);
+    if (value) {
+      // Split on whitespace and filter out invalid values.
+      value
+        .split(/\s+/)
+        .filter(isValidSizeValue)
+        .reduce((collector, size) => collector.add(size), sizes);
+    }
+    return sizes.size ? Array.from(sizes) : undefined;
+    // Implementation of HTML's link@size attribute checker.
+    function isValidSizeValue(aSize) {
+      const size = aSize.toLowerCase();
+      if (ImageObjectProcessor.anyRegEx.test(aSize)) {
+        return true;
+      }
+      if (!size.includes("x") || size.indexOf("x") !== size.lastIndexOf("x")) {
+        return false;
+      }
+      // Split left of x for width, after x for height.
+      const widthAndHeight = size.split("x");
+      const w = widthAndHeight.shift();
+      const h = widthAndHeight.join("x");
+      const validStarts = !w.startsWith("0") && !h.startsWith("0");
+      const validDecimals = ImageObjectProcessor.decimals.test(w + h);
+      return validStarts && validDecimals;
+    }
+  }
+};