Set callback to nullptr after sending success

Change-Id: Iecbf7ff7d7a8f636b55d251cc105bac1e22f4b5b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2362921
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Auto-Submit: Changhao Han <changhaohan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#800093}

third_party/blink/renderer/core/inspector/inspector_css_agent.cc

@@ -2616,6 +2616,7 @@ Response InspectorCSSAgent::trackComputedStyleUpdates(
     if (computed_style_updated_callback_) {
       computed_style_updated_callback_->sendSuccess(
           BuildArrayForComputedStyleUpdatedNodes());
+      computed_style_updated_callback_ = nullptr;
     }
     computed_style_updated_node_ids_.clear();
     return Response::Success();

third_party/blink/web_tests/inspector-protocol/css/css-poll-style-updates-expected.txt

@@ -11,11 +11,6 @@ Updated nodes from the second session should not contain the first item: true
 Updated nodes from the second session should contain the second item: true
 Updated nodes from the second session should contain the third item: true
 Updated nodes from the second session should not contain the fourth item: true
-Sending a request before the previous one is resolved should fail with an error message:
-{
-    code : -32000
-    message : A previous request has not been resolved yet.
-}
 Sending a request while no style is being tracked should fail with an error message:
 {
     code : -32000

third_party/blink/web_tests/inspector-protocol/css/css-poll-style-updates-multiple-requests-expected.txt

+Test multiple CSS.takeComputedStyleUpdates commands at the same time.
+Sending a request before the previous one is resolved should fail with an error message:
+{
+    code : -32000
+    message : A previous request has not been resolved yet.
+}
+[
+]
+Updated nodes should contain the first item: true
+Updated nodes should contain the second item: true
+Updated nodes should not contain the third item: true
+Updated nodes should not contain the fourth item: true
+

third_party/blink/web_tests/inspector-protocol/css/css-poll-style-updates-multiple-requests.js

+(async function (testRunner) {
+  const { page, session, dp } = await testRunner.startURL(
+    'resources/css-poll-style-updates.html',
+    'Test multiple CSS.takeComputedStyleUpdates commands at the same time.');
+
+  await dp.DOM.enable();
+  await dp.CSS.enable();
+
+  const CSSHelper = await testRunner.loadScript('../resources/css-helper.js');
+  const cssHelper = new CSSHelper(testRunner, dp);
+
+  const documentNodeId = await cssHelper.requestDocumentNodeId();
+  const nodeIds = await cssHelper.requestAllNodeIds(documentNodeId, '.item');
+
+  await dp.CSS.trackComputedStyleUpdates({
+    'propertiesToTrack': [
+      {
+        name: 'position',
+        value: 'relative',
+      },
+      {
+        name: 'position',
+        value: 'absolute',
+      }
+    ],
+  });
+
+  // Test multiple requests at the same time
+  const multipleRequestsPromise = Promise.all([
+    dp.CSS.takeComputedStyleUpdates(),
+    dp.CSS.takeComputedStyleUpdates(),
+  ]);
+
+  session.evaluate(
+    () =>
+      document.querySelector('.container').classList.add('change-2'));
+  // Only one request can be active at a time; other requests should fail.
+  const multipleRequestsResponse = await multipleRequestsPromise;
+  let errorResponse =
+    multipleRequestsResponse.find(result => Boolean(result.error));
+  testRunner.log(
+    'Sending a request before the previous one is resolved should fail with an error message:');
+  testRunner.log(errorResponse && errorResponse.error);
+
+  const pollBeforeDisablePromise = dp.CSS.takeComputedStyleUpdates();
+  await dp.CSS.trackComputedStyleUpdates({
+    'propertiesToTrack': [],
+  });
+  testRunner.log((await pollBeforeDisablePromise).result.nodeIds);
+
+  // Re-enable tracking and poll to see if the previous callback was correctly nullified
+  await dp.CSS.trackComputedStyleUpdates({
+    'propertiesToTrack': [
+      {
+        name: 'position',
+        value: 'relative',
+      },
+      {
+        name: 'position',
+        value: 'absolute',
+      }
+    ],
+  });
+
+  session.evaluate(
+    () =>
+      document.querySelector('.container').classList.remove('change-2'));
+
+  const pollAfterReEnableResult = await dp.CSS.takeComputedStyleUpdates();
+  const respondedIds = pollAfterReEnableResult.result.nodeIds;
+  testRunner.log(
+    `Updated nodes should contain the first item: ${
+      respondedIds.includes(nodeIds[0])}`);
+  testRunner.log(
+    `Updated nodes should contain the second item: ${
+      respondedIds.includes(nodeIds[1])}`);
+  testRunner.log(
+    `Updated nodes should not contain the third item: ${
+    !respondedIds.includes(nodeIds[2])}`);
+  testRunner.log(
+    `Updated nodes should not contain the fourth item: ${
+    !respondedIds.includes(nodeIds[3])}`);
+  testRunner.completeTest();
+});

third_party/blink/web_tests/inspector-protocol/css/css-poll-style-updates.js

@@ -116,22 +116,6 @@
     `Updated nodes from the second session should not contain the fourth item: ${
     !secondSessionRespondedIds.includes(secondSessionNodeIds[3])}`);
 
-  const multipleRequestsPromise = Promise.all([
-    firstDP.CSS.takeComputedStyleUpdates(),
-    firstDP.CSS.takeComputedStyleUpdates(),
-  ]);
-
-  firstSession.evaluate(
-    () =>
-      document.querySelector('.container').classList.remove('change-2'));
-  // Only one request can be active at a time; other requests should fail.
-  const multipleRequestsResponse = await multipleRequestsPromise;
-  let errorResponse =
-    multipleRequestsResponse.find(result => Boolean(result.error));
-  testRunner.log(
-    'Sending a request before the previous one is resolved should fail with an error message:');
-  testRunner.log(errorResponse && errorResponse.error);
-
   await firstDP.CSS.trackComputedStyleUpdates({
     'propertiesToTrack': [],
   });