[CRX] Migrate Chrome extension to Manifest Version 3

[Rob--W]

This PR updates the implementation of the Chrome extension to Manifest Version 3. If you're interested in the individual units of change, review the individual commits and their commit messages.

I manually tested this in Chrome 127, 128 and 130 (and also as old as Chrome 96). Scenarios tested include: http(s) PDFs, link click (verifying that Referer is set), file:-navigations.

Fixes #15161

[timvandermeij]

Looks good to me, with the comments below addressed. I'll have another look at this once that's done before setting the final approval because it's quite a bit of code changes, so I'd like to make sure I haven't missed anything in this round.

[Rob--W]

I've updated the code + rebased the PR. To more easily tell the real difference, here is the diff:

Output of: git diff 86293d43f 0d9d9debd

diff --git a/extensions/chromium/pdfHandler.js b/extensions/chromium/pdfHandler.js
index 024be2760..0fd71e9f1 100644
--- a/extensions/chromium/pdfHandler.js
+++ b/extensions/chromium/pdfHandler.js
@@ -81,7 +81,8 @@ async function registerPdfRedirectRule() {
       action: ACTION_IGNORE_OTHER_RULES,
     },
     {
-      // Do not redirect for URLs containing pdfjs.action=download.
+      // Redirect local PDF files if isAllowedFileSchemeAccess is true. No-op
+      // otherwise and then handled by webNavigation.onBeforeNavigate below.
       condition: {
         regexFilter: "^file://.*\\.pdf$",
         resourceTypes: ["main_frame", "sub_frame"],
@@ -192,7 +193,8 @@ async function registerPdfRedirectRule() {
     },
   ];
   for (const [i, rule] of addRules.entries()) {
-    rule.id = 15161 + i;
+    // id must be unique and at least 1, but i starts at 0. So add +1.
+    rule.id = i + 1;
     rule.priority = addRules.length - i;
   }
   try {
diff --git a/extensions/chromium/preserve-referer.js b/extensions/chromium/preserve-referer.js
index d4da5b8f2..92c628da3 100644
--- a/extensions/chromium/preserve-referer.js
+++ b/extensions/chromium/preserve-referer.js
@@ -34,7 +34,7 @@ limitations under the License.
 
 // g_referrers[tabId][frameId] = referrer of PDF frame.
 var g_referrers = {};
-var g_referrerTimer = {};
+var g_referrerTimers = {};
 // The background script will eventually suspend after 30 seconds of inactivity.
 // This can be delayed when extension events are firing. To prevent the data
 // from being kept in memory for too long, cap the data duration to 5 minutes.
@@ -46,26 +46,25 @@ var g_postRequests = {};
 var rIsReferer = /^referer$/i;
 chrome.webRequest.onSendHeaders.addListener(
   function saveReferer(details) {
-    if (!g_referrers[details.tabId]) {
-      g_referrers[details.tabId] = {};
-    }
-    g_referrers[details.tabId][details.frameId] = details.requestHeaders.find(
-      h => rIsReferer.test(h.name)
+    const { tabId, frameId, requestHeaders, method } = details;
+    g_referrers[tabId] ??= {};
+    g_referrers[tabId][frameId] = requestHeaders.find(h =>
+      rIsReferer.test(h.name)
     )?.value;
-    setCanRequestBody(details.tabId, details.frameId, details.method !== "GET");
-    forgetReferrerEventually(details.tabId);
+    setCanRequestBody(tabId, frameId, method !== "GET");
+    forgetReferrerEventually(tabId);
   },
   { urls: ["*://*/*"], types: ["main_frame", "sub_frame"] },
   ["requestHeaders", "extraHeaders"]
 );
 
 function forgetReferrerEventually(tabId) {
-  if (g_referrerTimer[tabId]) {
-    clearTimeout(g_referrerTimer[tabId]);
+  if (g_referrerTimers[tabId]) {
+    clearTimeout(g_referrerTimers[tabId]);
   }
-  g_referrerTimer[tabId] = setTimeout(() => {
+  g_referrerTimers[tabId] = setTimeout(() => {
     delete g_referrers[tabId];
-    delete g_referrerTimer[tabId];
+    delete g_referrerTimers[tabId];
     delete g_postRequests[tabId];
   }, REFERRER_IN_MEMORY_TIME);
 }
@@ -75,9 +74,7 @@ function forgetReferrerEventually(tabId) {
 // tracking, it is still here to enable re-use of the webRequest listener above.
 function setCanRequestBody(tabId, frameId, isPOST) {
   if (isPOST) {
-    if (!g_postRequests[tabId]) {
-      g_postRequests[tabId] = new Set();
-    }
+    g_postRequests[tabId] ??= new Set();
     g_postRequests[tabId].add(frameId);
   } else {
     g_postRequests[tabId]?.delete(frameId);

[Rob--W]

Addressed #18681 (comment)

Output of: git diff 0d9d9debd 4bf7be642

diff --git a/extensions/chromium/preserve-referer.js b/extensions/chromium/preserve-referer.js
index 92c628da3..b352dee36 100644
--- a/extensions/chromium/preserve-referer.js
+++ b/extensions/chromium/preserve-referer.js
@@ -112,7 +112,7 @@ chrome.runtime.onConnect.addListener(function onReceivePort(port) {
       referer = data.referer;
     }
     dnrRequestId = data.dnrRequestId;
-    setStickyReferrer(data.requestUrl, () => {
+    setStickyReferrer(dnrRequestId, tabId, data.requestUrl, referer, () => {
       // Acknowledge the message, and include the latest referer for this frame.
       port.postMessage(referer);
     });
@@ -120,41 +120,40 @@ chrome.runtime.onConnect.addListener(function onReceivePort(port) {
 
   // The port is only disconnected when the other end reloads.
   port.onDisconnect.addListener(function () {
-    unsetStickyReferrer();
+    unsetStickyReferrer(dnrRequestId);
   });
-  function setStickyReferrer(url, callback) {
-    if (!referer) {
-      unsetStickyReferrer();
-      callback();
-      return;
-    }
-    const rule = {
-      id: dnrRequestId,
-      condition: {
-        urlFilter: `|${url}|`,
-        // The viewer and background are presumed to have the same origin:
-        initiatorDomains: [location.hostname], // = chrome.runtime.id.
-        resourceTypes: ["xmlhttprequest"],
-        tabIds: [tabId],
-      },
-      action: {
-        type: "modifyHeaders",
-        requestHeaders: [
-          { operation: "set", header: "referer", value: referer },
-        ],
-      },
-    };
-    chrome.declarativeNetRequest.updateSessionRules(
-      { removeRuleIds: [dnrRequestId], addRules: [rule] },
-      callback
-    );
+});
+
+function setStickyReferrer(dnrRequestId, tabId, url, referer, callback) {
+  if (!referer) {
+    unsetStickyReferrer(dnrRequestId);
+    callback();
+    return;
   }
+  const rule = {
+    id: dnrRequestId,
+    condition: {
+      urlFilter: `|${url}|`,
+      // The viewer and background are presumed to have the same origin:
+      initiatorDomains: [location.hostname], // = chrome.runtime.id.
+      resourceTypes: ["xmlhttprequest"],
+      tabIds: [tabId],
+    },
+    action: {
+      type: "modifyHeaders",
+      requestHeaders: [{ operation: "set", header: "referer", value: referer }],
+    },
+  };
+  chrome.declarativeNetRequest.updateSessionRules(
+    { removeRuleIds: [dnrRequestId], addRules: [rule] },
+    callback
+  );
+}
 
-  function unsetStickyReferrer() {
-    if (dnrRequestId) {
-      chrome.declarativeNetRequest.updateSessionRules({
-        removeRuleIds: [dnrRequestId],
-      });
-    }
+function unsetStickyReferrer(dnrRequestId) {
+  if (dnrRequestId) {
+    chrome.declarativeNetRequest.updateSessionRules({
+      removeRuleIds: [dnrRequestId],
+    });
   }
-});
+}

Or perhaps a bit easier to review:

Output of: git diff 0d9d9debd 4bf7be642 --ignore-space-change

diff --git a/extensions/chromium/preserve-referer.js b/extensions/chromium/preserve-referer.js
index 92c628da3..b352dee36 100644
--- a/extensions/chromium/preserve-referer.js
+++ b/extensions/chromium/preserve-referer.js
@@ -112,7 +112,7 @@ chrome.runtime.onConnect.addListener(function onReceivePort(port) {
       referer = data.referer;
     }
     dnrRequestId = data.dnrRequestId;
-    setStickyReferrer(data.requestUrl, () => {
+    setStickyReferrer(dnrRequestId, tabId, data.requestUrl, referer, () => {
       // Acknowledge the message, and include the latest referer for this frame.
       port.postMessage(referer);
     });
@@ -120,11 +120,13 @@ chrome.runtime.onConnect.addListener(function onReceivePort(port) {
 
   // The port is only disconnected when the other end reloads.
   port.onDisconnect.addListener(function () {
-    unsetStickyReferrer();
+    unsetStickyReferrer(dnrRequestId);
   });
-  function setStickyReferrer(url, callback) {
+});
+
+function setStickyReferrer(dnrRequestId, tabId, url, referer, callback) {
   if (!referer) {
-      unsetStickyReferrer();
+    unsetStickyReferrer(dnrRequestId);
     callback();
     return;
   }
@@ -139,22 +141,19 @@ chrome.runtime.onConnect.addListener(function onReceivePort(port) {
     },
     action: {
       type: "modifyHeaders",
-        requestHeaders: [
-          { operation: "set", header: "referer", value: referer },
-        ],
+      requestHeaders: [{ operation: "set", header: "referer", value: referer }],
     },
   };
   chrome.declarativeNetRequest.updateSessionRules(
     { removeRuleIds: [dnrRequestId], addRules: [rule] },
     callback
   );
-  }
+}
 
-  function unsetStickyReferrer() {
+function unsetStickyReferrer(dnrRequestId) {
   if (dnrRequestId) {
     chrome.declarativeNetRequest.updateSessionRules({
       removeRuleIds: [dnrRequestId],
     });
   }
-  }
-});
+}

[timvandermeij]

Nice work; thank you!