--- a/dom/camera/test/test_camera_fake_parameters.html
+++ b/dom/camera/test/test_camera_fake_parameters.html
@@ -464,36 +464,32 @@ suite.test('bug-1054803', function() {
       cap.pictureSizes.forEach(function(capSize) {
         if (capSize.height == size.height && capSize.width == size.width) {
           ++found;
         }
       });
       ok(found == 1, "found size " + size.toSource() + " in pictureSizes");
     });
 
-    var sizeGenerator = Iterator(expSizes);
+    var sizeIterator = expSizes.values();
     return new Promise(function(resolve, reject) {
       function nextSize() {
-        try {
-          var size = sizeGenerator.next()[1];
-          var sync = suite.waitParameterPush();
-          cam.setPictureSize(size);
-          sync.then(function() {
-            var got = cam.getPictureSize();
-            ok(got.width == size.width && got.height == size.height,
-              "Set size " + size.toSource() + ", got size " + got.toSource());
-            nextSize();
-          }, reject);
-        } catch(e) {
-          if (e instanceof StopIteration) {
-            resolve();
-          } else {
-            reject(e);
-          }
+        var {value:size, done} = sizeIterator.next();
+        if (done) {
+          resolve();
+          return;
         }
+        var sync = suite.waitParameterPush();
+        cam.setPictureSize(size);
+        sync.then(function() {
+          var got = cam.getPictureSize();
+          ok(got.width == size.width && got.height == size.height,
+            "Set size " + size.toSource() + ", got size " + got.toSource());
+          nextSize();
+        }, reject);
       }
 
       nextSize();
     });
   }
 
   return suite.getCamera()
     .then(verify, suite.rejectGetCamera);

--- a/dom/svg/test/test_pathAnimInterpolation.xhtml
+++ b/dom/svg/test/test_pathAnimInterpolation.xhtml
@@ -188,17 +188,17 @@ function argumentNames(aType)
   return gArgumentNames[aType.toUpperCase()];
 }
 
 // Creates and returns a new element and sets some attributes on it.
 function newElement(aNamespaceURI, aLocalName, aAttributes)
 {
   var e = document.createElementNS(aNamespaceURI, aLocalName);
   if (aAttributes) {
-    for (let [name, value] in Iterator(aAttributes)) {
+    for (let [name, value] of Object.entries(aAttributes)) {
       e.setAttribute(name, value);
     }
   }
   return e;
 }
 
 // Creates and returns a new SVG element and sets some attributes on it.
 function newSVGElement(aLocalName, aAttributes)
@@ -267,17 +267,17 @@ function isValidInterpolation(aFromType,
 // Runs the test.
 function run()
 {
   for (let additive of [false, true]) {
     let indexOfExpectedArguments = additive ? 3 : 2;
 
     // Add subtests for each combination of prefix and suffix, and additive
     // or not.
-    for (let [typePair, suffixEntry] in Iterator(gSuffixes)) {
+    for (let [typePair, suffixEntry] of Object.entries(gSuffixes)) {
       let fromType = typePair[0],
           toType = typePair[1],
           fromArguments = suffixEntry[0],
           toArguments = suffixEntry[1],
           expectedArguments = suffixEntry[indexOfExpectedArguments];
 
       for (let prefixEntry of gPrefixes) {
         let [prefixLength, prefix] = prefixEntry;

--- a/dom/system/gonk/ril_worker.js
+++ b/dom/system/gonk/ril_worker.js
@@ -10442,18 +10442,17 @@ StkProactiveCmdHelperObject.prototype = 
     let nextActionList = [];
     for (let i = 0; i < length; i++) {
       nextActionList.push(GsmPDUHelper.readHexOctet());
     }
     return nextActionList;
   },
 
   searchForTag: function(tag, ctlvs) {
-    let iter = Iterator(ctlvs);
-    for (let [index, ctlv] in iter) {
+    for (let ctlv of ctlvs) {
       if ((ctlv.tag & ~COMPREHENSIONTLV_FLAG_CR) == tag) {
         return ctlv;
       }
     }
     return null;
   },
 
   searchForSelectedTags: function(ctlvs, tags) {
@@ -11050,17 +11049,17 @@ BerTlvHelperObject.prototype = {
    */
   retrieveFileIdentifier: function(length) {
     let GsmPDUHelper = this.context.GsmPDUHelper;
     return {fileId : (GsmPDUHelper.readHexOctet() << 8) +
                       GsmPDUHelper.readHexOctet()};
   },
 
   searchForNextTag: function(tag, iter) {
-    for (let [index, tlv] in iter) {
+    for (let tlv of iter) {
       if (tlv.tag === tag) {
         return tlv;
       }
     }
     return null;
   }
 };
 BerTlvHelperObject.prototype[BER_FCP_TEMPLATE_TAG] = function BER_FCP_TEMPLATE_TAG(length) {
@@ -11401,17 +11400,17 @@ ICCIOHelperObject.prototype = {
   /**
    * Helper function for processing USIM get response.
    */
   processUSimGetResponse: function(options, octetLen) {
     let BerTlvHelper = this.context.BerTlvHelper;
 
     let berTlv = BerTlvHelper.decode(octetLen);
     // See TS 102 221 Table 11.4 for the content order of getResponse.
-    let iter = Iterator(berTlv.value);
+    let iter = berTlv.value.values();
     let tlv = BerTlvHelper.searchForNextTag(BER_FCP_FILE_DESCRIPTOR_TAG,
                                             iter);
     if (!tlv ||
         (tlv.value.fileStructure !== UICC_EF_STRUCTURE[options.structure])) {
       throw new Error("Expected EF structure " +
                       UICC_EF_STRUCTURE[options.structure] +
                       " but read " + tlv.value.fileStructure);
     }

--- a/dom/system/gonk/tests/test_ril_worker_icc_BerTlvHelper.js
+++ b/dom/system/gonk/tests/test_ril_worker_icc_BerTlvHelper.js
@@ -28,17 +28,17 @@ add_test(function test_fcp_template_for_
     0x80, 0x02, 0x00, 0x0A,
     0x88, 0x01, 0x10];
 
   for (let i = 0; i < tag_test.length; i++) {
     pduHelper.writeHexOctet(tag_test[i]);
   }
 
   let berTlv = berHelper.decode(tag_test.length);
-  let iter = Iterator(berTlv.value);
+  let iter = berTlv.value.values();
   let tlv = berHelper.searchForNextTag(BER_FCP_FILE_DESCRIPTOR_TAG, iter);
   equal(tlv.value.fileStructure, UICC_EF_STRUCTURE[EF_STRUCTURE_TRANSPARENT]);
 
   tlv = berHelper.searchForNextTag(BER_FCP_FILE_IDENTIFIER_TAG, iter);
   equal(tlv.value.fileId, 0x2FE2);
 
   tlv = berHelper.searchForNextTag(BER_FCP_FILE_SIZE_DATA_TAG, iter);
   equal(tlv.value.fileSizeData, 0x0A);
@@ -66,17 +66,17 @@ add_test(function test_fcp_template_for_
     0x80, 0x02, 0x00, 0x1A,
     0x88, 0x00];
 
   for (let i = 0; i < tag_test.length; i++) {
     pduHelper.writeHexOctet(tag_test[i]);
   }
 
   let berTlv = berHelper.decode(tag_test.length);
-  let iter = Iterator(berTlv.value);
+  let iter = berTlv.value.values();
   let tlv = berHelper.searchForNextTag(BER_FCP_FILE_DESCRIPTOR_TAG, iter);
   equal(tlv.value.fileStructure, UICC_EF_STRUCTURE[EF_STRUCTURE_LINEAR_FIXED]);
   equal(tlv.value.recordLength, 0x1A);
   equal(tlv.value.numOfRecords, 0x01);
 
   tlv = berHelper.searchForNextTag(BER_FCP_FILE_IDENTIFIER_TAG, iter);
   equal(tlv.value.fileId, 0x6F40);