Adding initial functional version of extension

manifest.json

@@ -0,0 +1,30 @@
+{
+    "manifest_version": 2,
+
+    "name": "Tab Shortcuts",
+    "description": "This extension allows shortcuts for next / previous tabs to be reassigned",
+    "version": "0.1",
+
+    "permissions": [
+        "tabs"
+    ],
+
+    "commands" : {
+        "next-tab" : { 
+            "suggested_key" : { "default" : "Ctrl+J" },
+            "description" : "Go to next tab"
+        },
+        "prev-tab" : {
+            "suggested_key" : { "default" : "Ctrl+K" },
+            "description" : "Go to previous tab"
+        }, 
+        "remap-downloads" : {
+            "suggested_key" : { "default" : "Ctrl+Shift+J" },
+            "description" : "New downloads shortcut"
+        }
+    },
+
+    "background" : {
+        "scripts" : ["script.js"]
+    }
+}

script.js

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+var DL_URL = "chrome://downloads/";
+
+function change_tab(next_prev) {
+    chrome.tabs.query({currentWindow: true, active: true},  function(tabs) {
+        for (i in tabs) {
+            var tab = tabs[i];
+            chrome.tabs.query({windowId:tab.windowId}, function(alltabs) {
+                chrome.tabs.query({index: (next_prev(tab.index) + alltabs.length) % alltabs.length,
+                                    windowId:tab.windowId}, function(tabs) {
+                    for (i in tabs) {
+                        chrome.tabs.update(tabs[i].id, {active:true});
+                    }
+                });
+            });
+        }
+    });
+}
+
+function open_downloads() {
+    chrome.tabs.query({currentWindow: true, url: DL_URL}, function (tabs) {
+        var done = false;
+        for (i in tabs) {
+            chrome.tabs.update(tabs[i].id, {active:true});
+            done = true;
+        }
+        // if there is no existing downloads tab
+        if (done == false) {
+            chrome.tabs.create({url: DL_URL});
+        }
+    });
+}
+
+chrome.commands.onCommand.addListener(function(command) {
+    if (command == 'next-tab') {
+        change_tab(function(x) { return x + 1 });
+    }
+    if (command == 'prev-tab') {
+        change_tab(function(x) { return x - 1 });
+    }
+    if (command == 'remap-downloads') {
+        open_downloads();
+    }
+});