Bug 1778068 - Add a test to check that the colors used to render a pdf are the correct ones r=pdfjs-reviewers,marco

Differential Revision: https://phabricator.services.mozilla.com/D151380

toolkit/components/pdfjs/test/browser.ini

@@ -3,6 +3,9 @@ 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_fill_login.js]
 support-files =

toolkit/components/pdfjs/test/browser_pdfjs_hcm.js

@@ -0,0 +1,104 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+const RELATIVE_DIR = "toolkit/components/pdfjs/test/";
+const TESTROOT = "http://example.com/browser/" + RELATIVE_DIR;
+
+/**
+ * Get the first and last pixels on the drawn canvas.
+ * @param {Object} browser
+ * @returns {Object}
+ */
+async function getFirstLastPixels(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 = Array.from(
+      canvas.getContext("2d").getImageData(0, 0, canvas.width, canvas.height)
+        .data
+    );
+
+    return {
+      first: data.slice(0, 3),
+      last: data.slice(-4, -1),
+    };
+  });
+}
+
+/**
+ * Test that the pdf has the correct color depending on the high contrast mode.
+ */
+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 SpecialPowers.pushPrefEnv({
+    set: [
+      ["browser.display.document_color_use", 0],
+      ["browser.display.background_color", "#ff0000"],
+      ["browser.display.foreground_color", "#00ff00"],
+      ["browser.display.use_system_colors", false],
+    ],
+  });
+
+  await BrowserTestUtils.withNewTab(
+    { gBrowser, url: "about:blank" },
+    async function(browser) {
+      // check that PDF is opened with internal viewer
+      await waitForPdfJSCanvas(
+        browser,
+        `${TESTROOT}file_pdfjs_hcm.pdf#zoom=800`
+      );
+
+      const { first, last } = await getFirstLastPixels(browser);
+      // The first pixel must be black and not green.
+      Assert.deepEqual(first, [0, 0, 0]);
+
+      // The last pixel must be white and not red.
+      Assert.deepEqual(last, [255, 255, 255]);
+    }
+  );
+
+  // Enable HCM.
+  await SpecialPowers.pushPrefEnv({
+    set: [["ui.useAccessibilityTheme", 1]],
+  });
+
+  await BrowserTestUtils.withNewTab(
+    { gBrowser, url: "about:blank" },
+    async function(browser) {
+      // check that PDF is opened with internal viewer
+      await waitForPdfJSCanvas(
+        browser,
+        `${TESTROOT}file_pdfjs_hcm.pdf#zoom=800`
+      );
+
+      const { first, last } = await getFirstLastPixels(browser);
+      // The first pixel must be green.
+      Assert.deepEqual(first, [0, 255, 0]);
+
+      // The last pixel must be red.
+      Assert.deepEqual(last, [255, 0, 0]);
+    }
+  );
+});

toolkit/components/pdfjs/test/file_pdfjs_hcm.pdf

@@ -0,0 +1,24 @@
+%PDF-1.4
+1 0 obj <</Type /Catalog /Pages 2 0 R>>
+endobj
+2 0 obj <</Type /Pages /Kids [3 0 R] /Count 1>>
+endobj
+3 0 obj<</Type /Page /Parent 2 0 R /MediaBox [0 0 3 3] /Contents 4 0 R>>
+endobj
+4 0 obj
+<</Length 12>>
+stream
+0.5 w 0 0 0 RG 0 2.75 m 0.5 2.75 l s
+endstream
+endobj
+xref
+0 5
+0000000000 65535 f
+0000000009 00000 n
+0000000056 00000 n
+0000000111 00000 n
+0000000191 00000 n
+trailer <</Size 5/Root 1 0 R>>
+startxref
+275
+%%EOF

toolkit/components/pdfjs/test/head.js

@@ -27,6 +27,20 @@ async function waitForPdfJSAnnotationLayer(browser, url) {
   return loadPromise;
 }
 
+async function waitForPdfJSCanvas(browser, url) {
+  let loadPromise = BrowserTestUtils.waitForContentEvent(
+    browser,
+    "pagerendered",
+    false,
+    null,
+    true
+  );
+  await SpecialPowers.spawn(browser, [url], contentUrl => {
+    content.location = contentUrl;
+  });
+  return loadPromise;
+}
+
 async function waitForPdfJSSandbox(browser) {
   let loadPromise = BrowserTestUtils.waitForContentEvent(
     browser,