Checkpointing before removing grpc-web.

Javascript implementation of protobuf uses eval (https://github.com/protocolbuffers/protobuf/issues/7778), which isn't allowed in Chrome extensions v3 manifest.  But we need v3 manifest to use `chrome.tabGroups` API, so I don't see an easy way to use grpc from a Chrome plugin.  And, at the end of the day, we don't really gain that much from grpc in that small kind of project.

chrome.proto

@@ -6,8 +6,20 @@ package trackd;
 
 service Chrome {
     rpc session_changed(SessionChangedRequest) returns (google.protobuf.Empty);
+
+    rpc set_session_for_window_id(SetSessionForWindowIdRequest) returns (google.protobuf.Empty);
+    rpc set_active_window(SetActiveWindowRequest) returns (google.protobuf.Empty);
 }
 
 message SessionChangedRequest {
     string session_name = 1;
 }
+
+message SetSessionForWindowIdRequest {
+    string session_name = 1;
+    int64 window_id = 2;
+}
+
+message SetActiveWindowRequest {
+    int64 window_id = 3;
+}

chrome_extension/client_chrome.js

@@ -4,6 +4,44 @@ chrome.runtime.onInstalled.addListener(function() {
     const {SessionChangedRequest} = require('./chrome_pb.js');
     const {ChromeClient} = require('./chrome_grpc_web_pb.js');
 
+    function onFocusChanged(windowId) {
+        console.log(`${windowId} is focused`);
+
+        let groupId = windowToSessionMap.get(windowId);
+        chrome.tabGroups.get(groupId, group => {
+            console.log(`groupId: ${groupId}, group: ${group}`);
+        });
+    }
+
+    chrome.windows.onFocusChanged.addListener(onFocusChanged);
+
+    let windowToSessionMap = new Map();
+    windowToSessionMap.set(-1, -1);
+
+    chrome.windows.getAll({populate: true}, windows => {
+        console.log(windows);
+
+        windowToSessionMap.clear();
+
+        for (let window_ of windows) {
+            for (let tab of window_.tabs) {
+                if (tab.groupId != -1) {
+                    windowToSessionMap.set(window_.id, tab.groupId);
+                    break;
+                }
+            }
+            windowToSessionMap.set(window_.id, -2);
+        }
+
+        // The assumption is that as we just started, the Chrome should still be focused.
+        // It may be good to check in trackd though that Chrome's XWindow is indeed focused
+        // when this plugin reports so.
+        windows.getLastFocused({}, window_ => {
+            onFocusChanged(window_.id);
+        });
+    });
+
+
     let client = new ChromeClient('http://localhost:3142', null, null);
 
     let request = new SessionChangedRequest();

chrome_extension/manifest.json

@@ -6,12 +6,11 @@
     "activeTab",
     "declarativeContent",
     "sessions",
-    "storage"
+    "storage",
+    "tabGroups"
   ],
   "background": {
-    "scripts": ["main.js"],
-    "persistent": false
+    "service_worker": "main.js"
   },
-  "manifest_version": 2,
-  "content_security_policy": "script-src 'self' 'unsafe-eval'; object-src 'self'"
+  "manifest_version": 3
 }