prevent injecting wallet detection on unwanted pages

src/wxBackend.ts

@@ -463,11 +463,31 @@ export function wxMain() {
     }
   });
 
+  const tabTimers: {[n: number]: number[]} = {};
+
+  chrome.tabs.onRemoved.addListener((tabId, changeInfo) => {
+    let tt = tabTimers[tabId] || [];
+    for (let t of tt) {
+      chrome.extension.getBackgroundPage().clearTimeout(t);
+    }
+  });
   chrome.tabs.onUpdated.addListener((tabId, changeInfo) => {
     if (changeInfo.status != 'complete') {
       return;
     }
+    const timers: number[] = [];
+
+    const addRun = (dt: number) => {
+      const id = chrome.extension.getBackgroundPage().setTimeout(run, dt);
+      timers.push(id);
+    }
+
+    const run = () => {
+      timers.shift();
       chrome.tabs.get(tabId, (tab) => {
+        if (chrome.runtime.lastError) {
+          return;
+        }
         if (!tab.url || !tab.id) {
           return;
         }
@@ -480,18 +500,19 @@ export function wxMain() {
             document.dispatchEvent(new Event("taler-probe-result"));
           }
         `;
-      let run = () => {
         chrome.tabs.executeScript(tab.id!, { code, runAt: "document_start" });
-      };
-      run();
-      chrome.extension.getBackgroundPage().setTimeout(run, 50);
-      chrome.extension.getBackgroundPage().setTimeout(run, 300);
-      chrome.extension.getBackgroundPage().setTimeout(run, 2000);
-      chrome.extension.getBackgroundPage().setTimeout(run, 4000);
-      chrome.extension.getBackgroundPage().setTimeout(run, 8000);
-      chrome.extension.getBackgroundPage().setTimeout(run, 16000);
       });
+    };
 
+    addRun(0);
+    addRun(50);
+    addRun(300);
+    addRun(1000);
+    addRun(2000);
+    addRun(4000);
+    addRun(8000);
+    addRun(16000);
+    tabTimers[tabId] = timers;
   });
 
   chrome.extension.getBackgroundPage().setInterval(clearRateLimitCache, 5000);