Bug 1821408 - Add a test for testing SVG filters in pdf.js r=pdfjs-reviewers,emilio,marco

SVG filters weren't working correctly because of a mismatch between filter URI
and document URI. The problem has been fixed in:
  https://github.com/mozilla/pdf.js/pull/16153
and here's the test.

Differential Revision: https://phabricator.services.mozilla.com/D172223

toolkit/components/pdfjs/test/browser.ini

@@ -3,13 +3,17 @@ support-files =
   file_pdfjs_test.pdf
   head.js
 
-[browser_pdfjs_hcm.js]
-support-files =
-  file_pdfjs_hcm.pdf
 [browser_pdfjs_download_button.js]
+[browser_pdfjs_editing_contextmenu.js]
+skip-if = headless # the headless clipboard only recognizes unicode mime type
+   os == "win" && os_version == "6.1" # Skip on Azure - frequent failure
+[browser_pdfjs_editing_telemetry.js]
 [browser_pdfjs_fill_login.js]
 support-files =
   file_pdfjs_form.pdf
+[browser_pdfjs_filters.js]
+support-files =
+  file_pdfjs_transfer_map.pdf
 [browser_pdfjs_find.js]
 support-files =
   file_pdfjs_object_stream.pdf
@@ -18,9 +22,14 @@ support-files =
 [browser_pdfjs_form.js]
 support-files =
   file_pdfjs_form.pdf
+[browser_pdfjs_fullscreen.js]
+[browser_pdfjs_hcm.js]
+support-files =
+  file_pdfjs_hcm.pdf
 [browser_pdfjs_js.js]
 support-files =
   file_pdfjs_js.pdf
+[browser_pdfjs_load_telemetry.js]
 [browser_pdfjs_main.js]
 [browser_pdfjs_navigation.js]
 [browser_pdfjs_nonpdf_filename.js]
@@ -37,19 +46,13 @@ skip-if = os == 'linux' && bits == 64 # Bug 1773830
 support-files =
   file_pdfjs_object_stream.pdf
   file_pdfjs_object_stream.pdf^headers^
-[browser_pdfjs_savedialog.js]
-skip-if = verify
 [browser_pdfjs_saveas.js]
 support-files =
   !/toolkit/content/tests/browser/common/mockTransfer.js
   file_pdf_download_link.html
+[browser_pdfjs_savedialog.js]
+skip-if = verify
+[browser_pdfjs_secondary_toolbar_telemetry.js]
 [browser_pdfjs_views.js]
 [browser_pdfjs_zoom.js]
 skip-if = (verify && debug && (os == 'win'))
-[browser_pdfjs_editing_contextmenu.js]
-skip-if = headless # the headless clipboard only recognizes unicode mime type
-   os == "win" && os_version == "6.1" # Skip on Azure - frequent failure
-[browser_pdfjs_editing_telemetry.js]
-[browser_pdfjs_secondary_toolbar_telemetry.js]
-[browser_pdfjs_fullscreen.js]
-[browser_pdfjs_load_telemetry.js]

toolkit/components/pdfjs/test/browser_pdfjs_filters.js

@@ -0,0 +1,81 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+const RELATIVE_DIR = "toolkit/components/pdfjs/test/";
+const TESTROOT = "https://example.com/browser/" + RELATIVE_DIR;
+
+/**
+ * Get the number of red pixels in the canvas.
+ * @param {Object} browser
+ * @returns {Object}
+ */
+async function getRedPixels(browser) {
+  return SpecialPowers.spawn(browser, [], async function() {
+    const { document } = content;
+    const canvas = document.querySelector("canvas");
+
+    Assert.ok(!!canvas, "We must have a canvas");
+
+    const data = canvas
+      .getContext("2d")
+      .getImageData(0, 0, canvas.width, canvas.height).data;
+
+    let redPixels = 0;
+    let total = 0;
+
+    for (let i = 0, ii = data.length; i < ii; i += 4) {
+      const R = data[i];
+      const G = data[i + 1];
+      const B = data[i + 2];
+
+      if (R > 128 && R > 4 * G && R > 4 * B) {
+        redPixels += 1;
+      }
+      total += 1;
+    }
+
+    return [redPixels, total];
+  });
+}
+
+/**
+ * Test that the pdf has the correct color thanks to the SVG filters.
+ */
+add_task(async function test() {
+  let mimeService = Cc["@mozilla.org/mime;1"].getService(Ci.nsIMIMEService);
+  let handlerInfo = mimeService.getFromTypeAndExtension(
+    "application/pdf",
+    "pdf"
+  );
+
+  // Make sure pdf.js is the default handler.
+  is(
+    handlerInfo.alwaysAskBeforeHandling,
+    false,
+    "pdf handler defaults to always-ask is false"
+  );
+  is(
+    handlerInfo.preferredAction,
+    Ci.nsIHandlerInfo.handleInternally,
+    "pdf handler defaults to internal"
+  );
+
+  info("Pref action: " + handlerInfo.preferredAction);
+
+  await BrowserTestUtils.withNewTab(
+    { gBrowser, url: "about:blank" },
+    async function(browser) {
+      // check that PDF is opened with internal viewer
+      await waitForPdfJSCanvas(
+        browser,
+        `${TESTROOT}file_pdfjs_transfer_map.pdf#zoom=100`
+      );
+
+      const [redPixels, total] = await getRedPixels(browser);
+      Assert.ok(
+        redPixels / total >= 0.1,
+        `Not enough red pixels: only ${redPixels} / ${total} red pixels!`
+      );
+    }
+  );
+});