Bug 1646960 - imported patch ignore-blocked-preloads.diff r=bomsy

Differential Revision: https://phabricator.services.mozilla.com/D80856

devtools/client/netmonitor/test/browser_net_block-csp.js

@@ -8,7 +8,7 @@
  */
 
 add_task(async function() {
-  const { tab, monitor } = await initNetMonitor(CSP_URL, { requestCount: 3 });
+  const { tab, monitor } = await initNetMonitor(CSP_URL, { requestCount: 2 });
 
   const { document, store, windowRequire } = monitor.panelWin;
   const Actions = windowRequire("devtools/client/netmonitor/src/actions/index");
@@ -18,11 +18,10 @@ add_task(async function() {
 
   store.dispatch(Actions.batchEnable(false));
 
-  const wait = waitForNetworkEvents(monitor, 3);
+  const wait = waitForNetworkEvents(monitor, 2);
   tab.linkedBrowser.reload();
-  await wait;
-
   info("Waiting until the requests appear in netmonitor");
+  await wait;
 
   // Ensure the attempt to load a JS file shows a blocked CSP error
   verifyRequestItemTarget(
@@ -32,7 +31,7 @@ add_task(async function() {
     "GET",
     EXAMPLE_URL + "js_websocket-worker-test.js",
     {
-      transferred: "CSP Preload",
+      transferred: "CSP",
       cause: { type: "script" },
       type: "",
     }

devtools/server/actors/network-monitor/network-observer.js

@@ -326,6 +326,20 @@ NetworkObserver.prototype = {
       return;
     }
 
+    // Ignore preload requests to avoid duplicity request entries in
+    // the Network panel. If a preload fails (for whatever reason)
+    // then the platform kicks off another 'real' request.
+    const type = channel.loadInfo.internalContentPolicyType;
+    if (
+      type == Ci.nsIContentPolicy.TYPE_INTERNAL_SCRIPT_PRELOAD ||
+      type == Ci.nsIContentPolicy.TYPE_INTERNAL_MODULE_PRELOAD ||
+      type == Ci.nsIContentPolicy.TYPE_INTERNAL_IMAGE_PRELOAD ||
+      type == Ci.nsIContentPolicy.TYPE_INTERNAL_STYLESHEET_PRELOAD ||
+      type == Ci.nsIContentPolicy.TYPE_INTERNAL_FONT_PRELOAD
+    ) {
+      return;
+    }
+
     const blockedCode = channel.loadInfo.requestBlockingReason;
     this._httpResponseExaminer(subject, topic, blockedCode);
   },