14 files changed, 855 insertions, 0 deletions
diff --git a/dom/file/ipc/tests/browser.toml b/dom/file/ipc/tests/browser.toml
new file mode 100644
index 0000000000..a27ae63e87
--- /dev/null
+++ b/dom/file/ipc/tests/browser.toml
@@ -0,0 +1,7 @@
+[DEFAULT]
+support-files = ["empty.html"]
+
+["browser_ipcBlob.js"]
+
+["browser_ipcBlob_temporary.js"]
+support-files = ["temporary.sjs"]
diff --git a/dom/file/ipc/tests/browser_ipcBlob.js b/dom/file/ipc/tests/browser_ipcBlob.js
new file mode 100644
index 0000000000..5b46db7221
--- /dev/null
+++ b/dom/file/ipc/tests/browser_ipcBlob.js
@@ -0,0 +1,250 @@
+/* -*- Mode: javascript; tab-width: 2; indent-tabs-mode: nil; js-indent-level: 2 -*- */
+
+requestLongerTimeout(3);
+
+const BASE_URI = "http://mochi.test:8888/browser/dom/file/ipc/tests/empty.html";
+
+// More than 1mb memory blob childA-parent-childB.
+add_task(async function test_CtoPtoC_big() {
+  let tab1 = await BrowserTestUtils.openNewForegroundTab(gBrowser, BASE_URI);
+  let browser1 = gBrowser.getBrowserForTab(tab1);
+
+  let blob = await SpecialPowers.spawn(browser1, [], function () {
+    let innerBlob = new Blob([new Array(1024 * 1024).join("123456789ABCDEF")]);
+    return innerBlob;
+  });
+
+  ok(blob, "CtoPtoC-big: We have a blob!");
+  is(
+    blob.size,
+    new Array(1024 * 1024).join("123456789ABCDEF").length,
+    "CtoPtoC-big: The size matches"
+  );
+
+  let tab2 = await BrowserTestUtils.openNewForegroundTab(gBrowser, BASE_URI);
+  let browser2 = gBrowser.getBrowserForTab(tab2);
+
+  let status = await SpecialPowers.spawn(
+    browser2,
+    [blob],
+    function (innerBlob) {
+      return new Promise(resolve => {
+        let fr = new content.FileReader();
+        fr.readAsText(innerBlob);
+        fr.onloadend = function () {
+          resolve(fr.result == new Array(1024 * 1024).join("123456789ABCDEF"));
+        };
+      });
+    }
+  );
+
+  ok(status, "CtoPtoC-big: Data match!");
+
+  BrowserTestUtils.removeTab(tab1);
+  BrowserTestUtils.removeTab(tab2);
+});
+
+// Less than 1mb memory blob childA-parent-childB.
+add_task(async function test_CtoPtoC_small() {
+  let tab1 = await BrowserTestUtils.openNewForegroundTab(gBrowser, BASE_URI);
+  let browser1 = gBrowser.getBrowserForTab(tab1);
+
+  let blob = await SpecialPowers.spawn(browser1, [], function () {
+    let innerBlob = new Blob(["hello world!"]);
+    return innerBlob;
+  });
+
+  ok(blob, "CtoPtoC-small: We have a blob!");
+  is(blob.size, "hello world!".length, "CtoPtoC-small: The size matches");
+
+  let tab2 = await BrowserTestUtils.openNewForegroundTab(gBrowser, BASE_URI);
+  let browser2 = gBrowser.getBrowserForTab(tab2);
+
+  let status = await SpecialPowers.spawn(
+    browser2,
+    [blob],
+    function (innerBlob) {
+      return new Promise(resolve => {
+        let fr = new content.FileReader();
+        fr.readAsText(innerBlob);
+        fr.onloadend = function () {
+          resolve(fr.result == "hello world!");
+        };
+      });
+    }
+  );
+
+  ok(status, "CtoPtoC-small: Data match!");
+
+  BrowserTestUtils.removeTab(tab1);
+  BrowserTestUtils.removeTab(tab2);
+});
+
+// More than 1mb memory blob childA-parent-childB: BroadcastChannel
+add_task(async function test_CtoPtoC_bc_big() {
+  let tab1 = await BrowserTestUtils.openNewForegroundTab(gBrowser, BASE_URI);
+  let browser1 = gBrowser.getBrowserForTab(tab1);
+
+  await SpecialPowers.spawn(browser1, [], function () {
+    var bc = new content.BroadcastChannel("test");
+    bc.onmessage = function () {
+      bc.postMessage(
+        new Blob([new Array(1024 * 1024).join("123456789ABCDEF")])
+      );
+    };
+  });
+
+  let tab2 = await BrowserTestUtils.openNewForegroundTab(gBrowser, BASE_URI);
+  let browser2 = gBrowser.getBrowserForTab(tab2);
+
+  let status = await SpecialPowers.spawn(browser2, [], function () {
+    return new Promise(resolve => {
+      var bc = new content.BroadcastChannel("test");
+      bc.onmessage = function (e) {
+        let fr = new content.FileReader();
+        fr.readAsText(e.data);
+        fr.onloadend = function () {
+          resolve(fr.result == new Array(1024 * 1024).join("123456789ABCDEF"));
+        };
+      };
+
+      bc.postMessage("GO!");
+    });
+  });
+
+  ok(status, "CtoPtoC-broadcastChannel-big: Data match!");
+
+  BrowserTestUtils.removeTab(tab1);
+  BrowserTestUtils.removeTab(tab2);
+});
+
+// Less than 1mb memory blob childA-parent-childB: BroadcastChannel
+add_task(async function test_CtoPtoC_bc_small() {
+  let tab1 = await BrowserTestUtils.openNewForegroundTab(gBrowser, BASE_URI);
+  let browser1 = gBrowser.getBrowserForTab(tab1);
+
+  await SpecialPowers.spawn(browser1, [], function () {
+    var bc = new content.BroadcastChannel("test");
+    bc.onmessage = function () {
+      bc.postMessage(new Blob(["hello world!"]));
+    };
+  });
+
+  let tab2 = await BrowserTestUtils.openNewForegroundTab(gBrowser, BASE_URI);
+  let browser2 = gBrowser.getBrowserForTab(tab2);
+
+  let status = await SpecialPowers.spawn(browser2, [], function () {
+    return new Promise(resolve => {
+      var bc = new content.BroadcastChannel("test");
+      bc.onmessage = function (e) {
+        let fr = new content.FileReader();
+        fr.readAsText(e.data);
+        fr.onloadend = function () {
+          resolve(fr.result == "hello world!");
+        };
+      };
+
+      bc.postMessage("GO!");
+    });
+  });
+
+  ok(status, "CtoPtoC-broadcastChannel-small: Data match!");
+
+  BrowserTestUtils.removeTab(tab1);
+  BrowserTestUtils.removeTab(tab2);
+});
+
+// blob URL childA-parent-childB
+add_task(async function test_CtoPtoC_bc_small() {
+  let tab1 = await BrowserTestUtils.openNewForegroundTab(gBrowser, BASE_URI);
+  let browser1 = gBrowser.getBrowserForTab(tab1);
+
+  let blobURL = await SpecialPowers.spawn(browser1, [], function () {
+    return content.URL.createObjectURL(new content.Blob(["hello world!"]));
+  });
+
+  let tab2 = await BrowserTestUtils.openNewForegroundTab(gBrowser, BASE_URI);
+  let browser2 = gBrowser.getBrowserForTab(tab2);
+
+  let status = await SpecialPowers.spawn(
+    browser2,
+    [blobURL],
+    function (innerBlobURL) {
+      return new Promise(resolve => {
+        var xhr = new content.XMLHttpRequest();
+        xhr.open("GET", innerBlobURL);
+        xhr.onloadend = function () {
+          resolve(xhr.response == "hello world!");
+        };
+
+        xhr.send();
+      });
+    }
+  );
+
+  ok(status, "CtoPtoC-blobURL: Data match!");
+
+  BrowserTestUtils.removeTab(tab1);
+  BrowserTestUtils.removeTab(tab2);
+});
+
+// Multipart Blob childA-parent-childB.
+add_task(async function test_CtoPtoC_multipart() {
+  let tab1 = await BrowserTestUtils.openNewForegroundTab(gBrowser, BASE_URI);
+  let browser1 = gBrowser.getBrowserForTab(tab1);
+
+  let blob = await SpecialPowers.spawn(browser1, [], function () {
+    return new Blob(["!"]);
+  });
+
+  ok(blob, "CtoPtoC-multipart: We have a blob!");
+  is(blob.size, "!".length, "CtoPtoC-multipart: The size matches");
+
+  let newBlob = new Blob(["world", blob]);
+
+  let tab2 = await BrowserTestUtils.openNewForegroundTab(gBrowser, BASE_URI);
+  let browser2 = gBrowser.getBrowserForTab(tab2);
+
+  let status = await SpecialPowers.spawn(
+    browser2,
+    [newBlob],
+    function (innerBlob) {
+      return new Promise(resolve => {
+        let fr = new content.FileReader();
+        fr.readAsText(new Blob(["hello ", innerBlob]));
+        fr.onloadend = function () {
+          resolve(fr.result == "hello world!");
+        };
+      });
+    }
+  );
+
+  ok(status, "CtoPtoC-multipart: Data match!");
+
+  BrowserTestUtils.removeTab(tab1);
+  BrowserTestUtils.removeTab(tab2);
+});
+
+// Multipart Blob childA-parent with a max size
+add_task(async function test_CtoPsize_multipart() {
+  let tab = await BrowserTestUtils.openNewForegroundTab(gBrowser, BASE_URI);
+  let browser = gBrowser.getBrowserForTab(tab);
+
+  let blob = await SpecialPowers.spawn(browser, [], function () {
+    let data = new Array(1024 * 512).join("A");
+    let blob1 = new Blob([data]);
+    let blob2 = new Blob([data]);
+    let blob3 = new Blob([data]);
+
+    return new Blob([blob1, blob2, blob3]);
+  });
+
+  ok(blob, "CtoPsize-multipart: We have a blob!");
+  is(
+    blob.size,
+    new Array(1024 * 512).join("A").length * 3,
+    "CtoPsize-multipart: The size matches"
+  );
+
+  BrowserTestUtils.removeTab(tab);
+});
diff --git a/dom/file/ipc/tests/browser_ipcBlob_temporary.js b/dom/file/ipc/tests/browser_ipcBlob_temporary.js
new file mode 100644
index 0000000000..56952e849f
--- /dev/null
+++ b/dom/file/ipc/tests/browser_ipcBlob_temporary.js
@@ -0,0 +1,115 @@
+/* -*- Mode: javascript; tab-width: 2; indent-tabs-mode: nil; js-indent-level: 2 -*- */
+
+requestLongerTimeout(3);
+
+const BASE_URI = "http://mochi.test:8888/browser/dom/file/ipc/tests/empty.html";
+
+add_task(async function test() {
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      ["dom.blob.memoryToTemporaryFile", 1],
+      ["dom.ipc.processCount", 4],
+    ],
+  });
+
+  let tab1 = await BrowserTestUtils.openNewForegroundTab(gBrowser, BASE_URI);
+  let browser1 = gBrowser.getBrowserForTab(tab1);
+
+  let tab2 = await BrowserTestUtils.openNewForegroundTab(gBrowser, BASE_URI);
+  let browser2 = gBrowser.getBrowserForTab(tab2);
+
+  await SpecialPowers.spawn(browser2, [], function () {
+    content.window.testPromise = new content.window.Promise(resolve => {
+      let bc = new content.window.BroadcastChannel("foobar");
+      bc.onmessage = e => {
+        function realTest() {
+          return new content.window.Promise(innerResolve => {
+            let count = 10;
+            for (let i = 0; i < count; ++i) {
+              info("FileReader at the same time: " + i);
+              let fr = new content.window.FileReader();
+              fr.readAsText(e.data);
+              fr.onerror = () => {
+                ok(false, "Something wrong happened.");
+              };
+
+              fr.onloadend = () => {
+                is(fr.result.length, e.data.size, "FileReader worked fine.");
+                if (!--count) {
+                  innerResolve(true);
+                }
+              };
+            }
+          });
+        }
+
+        let promises = [];
+        for (let i = 0; i < 5; ++i) {
+          promises.push(realTest());
+        }
+
+        Promise.all(promises).then(() => {
+          resolve(true);
+        });
+      };
+    });
+  });
+
+  let status = await SpecialPowers.spawn(browser1, [], function () {
+    let p = new content.window.Promise(resolve => {
+      let xhr = new content.window.XMLHttpRequest();
+      xhr.open("GET", "temporary.sjs", true);
+      xhr.responseType = "blob";
+      xhr.onload = () => {
+        resolve(xhr.response);
+      };
+      xhr.send();
+    });
+
+    return p.then(blob => {
+      function realTest() {
+        return new content.window.Promise(resolve => {
+          info("Let's broadcast the blob...");
+          let bc = new content.window.BroadcastChannel("foobar");
+          bc.postMessage(blob);
+
+          info("Here the test...");
+          let count = 10;
+          for (let i = 0; i < count; ++i) {
+            info("FileReader at the same time: " + i);
+            let fr = new content.window.FileReader();
+            fr.readAsText(blob);
+            fr.onerror = () => {
+              ok(false, "Something wrong happened.");
+            };
+
+            fr.onloadend = () => {
+              is(fr.result.length, blob.size, "FileReader worked fine.");
+              if (!--count) {
+                resolve(true);
+              }
+            };
+          }
+        });
+      }
+
+      let promises = [];
+      for (let i = 0; i < 5; ++i) {
+        promises.push(realTest());
+      }
+
+      return Promise.all(promises);
+    });
+  });
+
+  ok(status, "All good for tab1!");
+
+  status = await SpecialPowers.spawn(browser2, [], function () {
+    return content.window.testPromise;
+  });
+
+  ok(status, "All good for tab2!");
+
+  BrowserTestUtils.removeTab(tab1);
+  BrowserTestUtils.removeTab(tab2);
+});
diff --git a/dom/file/ipc/tests/empty.html b/dom/file/ipc/tests/empty.html
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/dom/file/ipc/tests/empty.html
diff --git a/dom/file/ipc/tests/green.jpg b/dom/file/ipc/tests/green.jpg
new file mode 100644
index 0000000000..48c454d27c
--- /dev/null
+++ b/dom/file/ipc/tests/green.jpg
diff --git a/dom/file/ipc/tests/mochitest.toml b/dom/file/ipc/tests/mochitest.toml
new file mode 100644
index 0000000000..73e25bba06
--- /dev/null
+++ b/dom/file/ipc/tests/mochitest.toml
@@ -0,0 +1,18 @@
+[DEFAULT]
+support-files = ["script_file.js"]
+
+["test_ipcBlob_createImageBitmap.html"]
+support-files = ["green.jpg"]
+skip-if = [
+  "http3",
+  "http2",
+]
+
+["test_ipcBlob_emptyMultiplex.html"]
+
+["test_ipcBlob_fileReaderSync.html"]
+
+["test_ipcBlob_mixedMultiplex.html"]
+support-files = ["ok.sjs"]
+
+["test_ipcBlob_workers.html"]
diff --git a/dom/file/ipc/tests/ok.sjs b/dom/file/ipc/tests/ok.sjs
new file mode 100644
index 0000000000..42f65733d9
--- /dev/null
+++ b/dom/file/ipc/tests/ok.sjs
@@ -0,0 +1,11 @@
+const CC = Components.Constructor;
+const BinaryInputStream = CC(
+  "@mozilla.org/binaryinputstream;1",
+  "nsIBinaryInputStream",
+  "setInputStream"
+);
+
+function handleRequest(request, response) {
+  response.setHeader("Content-Type", "text/html", false);
+  response.write(request.getHeader("Content-Length"));
+}
diff --git a/dom/file/ipc/tests/script_file.js b/dom/file/ipc/tests/script_file.js
new file mode 100644
index 0000000000..03cefeb3f1
--- /dev/null
+++ b/dom/file/ipc/tests/script_file.js
@@ -0,0 +1,52 @@
+/* eslint-env mozilla/chrome-script */
+
+// eslint-disable-next-line mozilla/reject-importGlobalProperties
+Cu.importGlobalProperties(["File"]);
+
+addMessageListener("file.open", function (e) {
+  var testFile = Services.dirsvc
+    .QueryInterface(Ci.nsIProperties)
+    .get("ProfD", Ci.nsIFile);
+  testFile.append("ipc_fileReader_testing");
+  testFile.createUnique(Ci.nsIFile.NORMAL_FILE_TYPE, 0o600);
+
+  var outStream = Cc[
+    "@mozilla.org/network/file-output-stream;1"
+  ].createInstance(Ci.nsIFileOutputStream);
+  outStream.init(
+    testFile,
+    0x02 | 0x08 | 0x20, // write, create, truncate
+    0o666,
+    0
+  );
+
+  var fileData = "Hello World!";
+  outStream.write(fileData, fileData.length);
+  outStream.close();
+
+  File.createFromNsIFile(testFile).then(function (file) {
+    sendAsyncMessage("file.opened", { file });
+  });
+});
+
+addMessageListener("emptyfile.open", function (e) {
+  var testFile = Services.dirsvc
+    .QueryInterface(Ci.nsIProperties)
+    .get("ProfD", Ci.nsIFile);
+  testFile.append("ipc_fileReader_testing");
+  testFile.createUnique(Ci.nsIFile.NORMAL_FILE_TYPE, 0o600);
+
+  var outStream = Cc[
+    "@mozilla.org/network/file-output-stream;1"
+  ].createInstance(Ci.nsIFileOutputStream);
+  outStream.init(
+    testFile,
+    0x02 | 0x08 | 0x20, // write, create, truncate
+    0o666,
+    0
+  );
+
+  File.createFromNsIFile(testFile).then(function (file) {
+    sendAsyncMessage("emptyfile.opened", { file });
+  });
+});
diff --git a/dom/file/ipc/tests/temporary.sjs b/dom/file/ipc/tests/temporary.sjs
new file mode 100644
index 0000000000..76db4e2f2e
--- /dev/null
+++ b/dom/file/ipc/tests/temporary.sjs
@@ -0,0 +1,6 @@
+function handleRequest(request, response) {
+  response.setHeader("Content-Type", "text/plain", false);
+
+  var data = new Array(1024 * 64).join("1234567890ABCDEF");
+  response.bodyOutputStream.write(data, data.length);
+}
diff --git a/dom/file/ipc/tests/test_ipcBlob_createImageBitmap.html b/dom/file/ipc/tests/test_ipcBlob_createImageBitmap.html
new file mode 100644
index 0000000000..27e8079229
--- /dev/null
+++ b/dom/file/ipc/tests/test_ipcBlob_createImageBitmap.html
@@ -0,0 +1,84 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <title>Test IPCBlob and CreateImageBitmap</title>
+  <script type="text/javascript" src="/MochiKit/MochiKit.js"></script>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+</head>
+<body>
+<script type="text/javascript">
+
+SimpleTest.waitForExplicitFinish();
+
+function test_mainThread() {
+  let bc = new BroadcastChannel('testMainThread');
+  bc.onmessage = e => {
+    createImageBitmap(e.data).then(image => {
+      ok(image.height, "this image has a valid size.");
+    }, () => {
+      ok(false, "error creating the image!");
+    }).then(next);
+  }
+
+  fetch('green.jpg').then(r => r.blob()).then(blob => {
+    let innerBc = new BroadcastChannel('testMainThread');
+    innerBc.postMessage(blob);
+  });
+}
+
+function test_worker() {
+  function workerScript() {
+    function ok(a, msg) { postMessage({ type: 'test', status: !!a, msg }); };
+    function finish() { postMessage({ type: 'finish' }); };
+
+    let bc = new BroadcastChannel('testWorker');
+    bc.onmessage = e => {
+      createImageBitmap(e.data).then(image => {
+        ok(image.height, "this image has a valid size.");
+      }, () => {
+        ok(false, "error creating the image!");
+      }).then(finish);
+    }
+
+    fetch('http://mochi.test:8888/tests/dom/file/ipc/tests/green.jpg').then(r => r.blob()).then(blob => {
+      let innerBc = new BroadcastChannel('testWorker');
+      innerBc.postMessage(blob);
+    });
+  }
+  let workerUrl = URL.createObjectURL(new Blob(["(", workerScript.toString(), ")()"]));
+  let worker = new Worker(workerUrl);
+
+  worker.onmessage = event => {
+    if (event.data.type == 'test') {
+      ok(event.data.status, event.data.msg);
+      return;
+    }
+
+    if (event.data.type == 'finish') {
+      next();
+    }
+  }
+}
+
+let tests = [
+  test_mainThread,
+  test_worker,
+];
+
+function next() {
+  if (!tests.length) {
+    SimpleTest.finish();
+    return;
+  }
+
+  let test = tests.shift();
+  test();
+}
+
+next();
+
+</script>
+</pre>
+</body>
+</html>
diff --git a/dom/file/ipc/tests/test_ipcBlob_emptyMultiplex.html b/dom/file/ipc/tests/test_ipcBlob_emptyMultiplex.html
new file mode 100644
index 0000000000..0487069467
--- /dev/null
+++ b/dom/file/ipc/tests/test_ipcBlob_emptyMultiplex.html
@@ -0,0 +1,45 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <title>Test an empty IPCBlob together with other parts</title>
+  <script type="text/javascript" src="/MochiKit/MochiKit.js"></script>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+</head>
+<body>
+<script type="text/javascript">
+
+function checkContent(msg, content) {
+  return new Promise(resolve => {
+    let fr = new FileReader();
+    fr.readAsText(new Blob(content));
+    fr.onloadend = () => {
+      is(fr.result, "Hello world!", "The content matches: " + msg);
+      resolve();
+    };
+  });
+}
+
+SimpleTest.waitForExplicitFinish();
+
+let url = SimpleTest.getTestFileURL("script_file.js");
+
+let script = SpecialPowers.loadChromeScript(url);
+script.addMessageListener("emptyfile.opened", message => {
+  checkContent("middle", ["Hello ", message.file, "world!"]).
+  then(() => checkContent("begin", [message.file, "Hello world!"])).
+  then(() => checkContent("end", ["Hello world!", message.file])).
+  then(() => checkContent("random", [message.file, message.file, "Hello world!", message.file])).
+  then(() => checkContent("random 2", [message.file, message.file, "Hello ",
+                                       message.file, "world", message.file,
+                                       message.file, "!", message.file, "",
+                                       message.file, message.file])).
+  then(SimpleTest.finish);
+});
+
+script.sendAsyncMessage("emptyfile.open");
+
+</script>
+</pre>
+</body>
+</html>
diff --git a/dom/file/ipc/tests/test_ipcBlob_fileReaderSync.html b/dom/file/ipc/tests/test_ipcBlob_fileReaderSync.html
new file mode 100644
index 0000000000..cbf8156e6e
--- /dev/null
+++ b/dom/file/ipc/tests/test_ipcBlob_fileReaderSync.html
@@ -0,0 +1,102 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <title>Test IPCBlob and FileReaderSync</title>
+  <script type="text/javascript" src="/MochiKit/MochiKit.js"></script>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+</head>
+<body>
+<script type="text/javascript">
+
+function workerScript() {
+  // Available to workers.
+  /* global FileReaderSync */
+  onmessage = function(event) {
+    let readerMemoryBlob = new FileReaderSync();
+    let status = readerMemoryBlob.readAsText(new Blob(['hello world'])) == 'hello world';
+    postMessage({ status, message: "FileReaderSync with memory blob still works" });
+
+    let readerIPCBlob1 = new FileReaderSync();
+    postMessage({ blob: event.data, method: 'readAsText',
+                  data: readerIPCBlob1.readAsText(event.data)});
+
+    let readerIPCBlob2 = new FileReaderSync();
+    postMessage({ blob: event.data, method: 'readAsArrayBuffer',
+                  data: readerIPCBlob2.readAsArrayBuffer(event.data)});
+
+    let readerIPCBlob3 = new FileReaderSync();
+    postMessage({ blob: event.data, method: 'readAsDataURL',
+                  data: readerIPCBlob3.readAsDataURL(event.data)});
+
+    let multipartBlob = new Blob(['wow', event.data]);
+
+    let readerIPCBlobMultipart1 = new FileReaderSync();
+    postMessage({ blob: multipartBlob, method: 'readAsText',
+                  data: readerIPCBlobMultipart1.readAsText(multipartBlob)});
+
+    let readerIPCBlobMultipart2 = new FileReaderSync();
+    postMessage({ blob: multipartBlob, method: 'readAsArrayBuffer',
+                  data: readerIPCBlobMultipart2.readAsArrayBuffer(multipartBlob)});
+
+    let readerIPCBlobMultipart3 = new FileReaderSync();
+    postMessage({ blob: multipartBlob, method: 'readAsDataURL',
+                  data: readerIPCBlobMultipart3.readAsDataURL(multipartBlob)});
+
+    postMessage({ finish: true });
+  }
+}
+
+let completed = false;
+let pendingTasks = 0;
+function maybeFinish() {
+  if (completed && !pendingTasks) {
+    SimpleTest.finish();
+  }
+}
+
+let workerUrl = URL.createObjectURL(new Blob(["(", workerScript.toString(), ")()"]));
+let worker = new Worker(workerUrl);
+worker.onmessage = event => {
+  if ("status" in event.data) {
+    ok(event.data.status, event.data.message);
+    return;
+  }
+
+  if ("blob" in event.data) {
+    let fr = new FileReader();
+    fr[event.data.method](event.data.blob);
+    ++pendingTasks;
+    fr.onload = () => {
+      if (event.data.method != 'readAsArrayBuffer') {
+        is(event.data.data, fr.result, "The file has been read");
+      } else {
+        is(event.data.data.byteLength, fr.result.byteLength, "The file has been read");
+      }
+      --pendingTasks;
+      maybeFinish();
+    }
+
+    return;
+  }
+
+  if ("finish" in event.data) {
+    completed = true;
+    maybeFinish();
+  }
+};
+
+let url = SimpleTest.getTestFileURL("script_file.js");
+let script = SpecialPowers.loadChromeScript(url);
+script.addMessageListener("file.opened", message => {
+  worker.postMessage(message.file);
+});
+
+script.sendAsyncMessage("file.open");
+
+SimpleTest.waitForExplicitFinish();
+
+</script>
+</pre>
+</body>
+</html>
diff --git a/dom/file/ipc/tests/test_ipcBlob_mixedMultiplex.html b/dom/file/ipc/tests/test_ipcBlob_mixedMultiplex.html
new file mode 100644
index 0000000000..c8e046fa88
--- /dev/null
+++ b/dom/file/ipc/tests/test_ipcBlob_mixedMultiplex.html
@@ -0,0 +1,41 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <title>Test an empty IPCBlob together with other parts</title>
+  <script type="text/javascript" src="/MochiKit/MochiKit.js"></script>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+</head>
+<body>
+<script type="text/javascript">
+
+let url = SimpleTest.getTestFileURL("script_file.js");
+let data = new Array(1024*1024).join('A');
+
+let script = SpecialPowers.loadChromeScript(url);
+script.addMessageListener("file.opened", message => {
+  let blob = new Blob([data]);
+
+  let form = new FormData();
+  form.append("blob1", blob);
+  form.append("blob2", message.file);
+  form.append("blob3", blob);
+
+  fetch("ok.sjs", {
+    method: "POST",
+    body: form,
+  })
+  .then(r => r.text())
+  .then(r => {
+    ok(parseInt(r, 10) > (data.length * 2), "We have data");
+  })
+  . then(SimpleTest.finish);
+});
+
+script.sendAsyncMessage("file.open");
+SimpleTest.waitForExplicitFinish();
+
+</script>
+</pre>
+</body>
+</html>
diff --git a/dom/file/ipc/tests/test_ipcBlob_workers.html b/dom/file/ipc/tests/test_ipcBlob_workers.html
new file mode 100644
index 0000000000..23e8963bb2
--- /dev/null
+++ b/dom/file/ipc/tests/test_ipcBlob_workers.html
@@ -0,0 +1,124 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <title>Test IPCBlob and Workers</title>
+  <script type="text/javascript" src="/MochiKit/MochiKit.js"></script>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+</head>
+<body>
+<script type="text/javascript">
+
+// Available to workers.
+/* global FileReaderSync */
+
+function test_workerOwner() {
+  info("test_workerOwner");
+
+  function workerScript() {
+    onmessage = e => {
+      e.ports[0].onmessage = event => {
+        let reader = new FileReader();
+        reader.readAsText(event.data);
+        reader.onloadend = () => {
+          let status = reader.result == 'hello world';
+          postMessage(status);
+        }
+      }
+    }
+  }
+
+  let mc = new MessageChannel();
+  mc.port1.postMessage(new Blob(['hello world']));
+
+  let workerUrl = URL.createObjectURL(new Blob(["(", workerScript.toString(), ")()"]));
+  let worker = new Worker(workerUrl);
+
+  worker.postMessage("", [mc.port2]);
+  worker.onmessage = event => {
+    ok(event.data, "All is done!");
+    next();
+  }
+}
+
+function test_workerToMainThread() {
+  info("test_workerToMainThread");
+  function workerScript() {
+    onmessage = e => {
+      e.ports[0].onmessage = event => {
+        postMessage(event.data);
+      }
+    }
+  }
+
+  let mc = new MessageChannel();
+  mc.port1.postMessage(new Blob(['hello world']));
+
+  let workerUrl = URL.createObjectURL(new Blob(["(", workerScript.toString(), ")()"]));
+  let worker = new Worker(workerUrl);
+
+  worker.postMessage("", [mc.port2]);
+  worker.onmessage = event => {
+    info("Blob received back, terminate the worker and force GC");
+    worker.terminate();
+    worker = null;
+    SpecialPowers.forceGC();
+
+    var fr = new FileReader();
+    fr.readAsText(event.data);
+    fr.onloadend = () => {
+      is(fr.result, "hello world", "Data matches");
+      next();
+    }
+  }
+}
+
+function test_workerOwnerPlusFileReaderSync() {
+  info("test_workerOwnerPlusFileReaderSync");
+
+  function workerScript() {
+    onmessage = e => {
+      e.ports[0].onmessage = event => {
+        let reader = new FileReaderSync();
+        let status = reader.readAsText(event.data) == 'hello world';
+         postMessage(status);
+      }
+    }
+  }
+
+  let mc = new MessageChannel();
+  mc.port1.postMessage(new Blob(['hello world']));
+
+  let workerUrl = URL.createObjectURL(new Blob(["(", workerScript.toString(), ")()"]));
+  let worker = new Worker(workerUrl);
+
+  worker.postMessage("", [mc.port2]);
+  worker.onmessage = event => {
+    ok(event.data, "All is done!");
+    next();
+  }
+}
+
+var tests = [
+  test_workerOwner,
+  test_workerToMainThread,
+  test_workerOwnerPlusFileReaderSync,
+];
+
+function next() {
+  if (!tests.length) {
+    SimpleTest.finish();
+    return;
+  }
+
+  var test = tests.shift();
+  test();
+}
+
+SimpleTest.waitForExplicitFinish();
+next();
+
+</script>
+</pre>
+</body>
+</html>