Bug 1707823 - [devtools] Replace usage of navigateTo in browser_toolbox_backward_forward_navigation.js. r=ochameau.

the test document has a script that adds dom nodes, js sources and stylesheet
to the document every 200ms. It might that the navigateTo call we were using to navigate
to the document would never resolve, as the load event won't fire because of the constant
addition of stylesheets and scripts.
This is fixed by not using navigateTo, as we don't really need the document to be ready,
but only register the navigation so later in the test we can do backward and forward navigations.

Differential Revision: https://phabricator.services.mozilla.com/D113480

devtools/client/framework/test/browser_toolbox_backward_forward_navigation.js

@@ -19,18 +19,34 @@ Services.scriptloader.loadSubScript(
 );
 
 add_task(async function() {
-  // Start with a page without much activity so the toolbox gets initialized safely
-  const tab = await addTab(`data:text/html,<meta charset=utf8>`);
+  // Don't show the third panel to limit the logs and activity.
+  await pushPref("devtools.inspector.three-pane-enabled", false);
+  await pushPref("devtools.inspector.activeSidebar", "ruleview");
+  const DATA_URL = `data:text/html,<meta charset=utf8>`;
+  const tab = await addTab(DATA_URL);
 
   // Select the debugger so there will be more activity
   const toolbox = await openToolboxForTab(tab, "jsdebugger");
   const inspector = await toolbox.selectTool("inspector");
 
   info("Navigate to the ORG test page");
-  await navigateTo(TEST_URI_ORG);
+  // We don't use `navigateTo` as the page is adding stylesheets and js files which might
+  // delay the load event indefinitely (and we don't need for anything to be loaded, or
+  // ready, just to register the initial navigation so we can go back and forth between urls)
+  let onLocationChange = BrowserTestUtils.waitForLocationChange(
+    gBrowser,
+    TEST_URI_ORG
+  );
+  BrowserTestUtils.loadURI(gBrowser, TEST_URI_ORG);
+  await onLocationChange;
 
   info("And then navigate to a different origin");
-  await navigateTo(TEST_URI_COM);
+  onLocationChange = BrowserTestUtils.waitForLocationChange(
+    gBrowser,
+    TEST_URI_COM
+  );
+  BrowserTestUtils.loadURI(gBrowser, TEST_URI_COM);
+  await onLocationChange;
 
   info(
     "Navigate backward and forward multiple times between the two origins, with different delays"
@@ -40,12 +56,18 @@ add_task(async function() {
   // Navigate one last time to a document with less activity so we don't have to deal
   // with pending promises when we destroy the toolbox
   const onInspectorReloaded = inspector.once("reloaded");
+  info("Navigate to final document");
   await navigateTo(`${TEST_URI_ORG}?no-mutation`);
+  info("Waiting for inspector to reload…");
   await onInspectorReloaded;
+  info("-> inspector reloaded");
   await checkToolboxState(toolbox);
 });
 
 add_task(async function() {
+  // Don't show the third panel to limit the logs and activity.
+  await pushPref("devtools.inspector.three-pane-enabled", false);
+  await pushPref("devtools.inspector.activeSidebar", "ruleview");
   const DATA_URL = `data:text/html,<meta charset=utf8>`;
   const tab = await addTab(DATA_URL);
 
@@ -65,8 +87,11 @@ add_task(async function() {
   // Navigate one last time to a document with less activity so we don't have to deal
   // with pending promises when we destroy the toolbox
   const onInspectorReloaded = inspector.once("reloaded");
+  info("Navigate to final document");
   await navigateTo(`${TEST_URI_ORG}?no-mutation`);
+  info("Waiting for inspector to reload…");
   await onInspectorReloaded;
+  info("-> inspector reloaded");
   await checkToolboxState(toolbox);
 });