[devtools] Support preSuspendModel and postResumeModel hooks

This CL is a preparation for an upcoming CL, in which CoverageModel
starts supporting suspendModel/resumeModel. CoverageModel needs to
perform actions that still/already require the other models to be
suspended/resumed, so this will make use of the new hooks.

Drive-by: Don't start shutting down models while still polling
          data from them.

Bug: chromium:1000155, chromium:1002427
Change-Id: I98f318daa909b129d992bdc142d1b3a6ed0adefd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1795442
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Alexei Filippov <alph@chromium.org>
Cr-Commit-Position: refs/heads/master@{#697546}

third_party/blink/renderer/devtools/front_end/coverage/CoverageModel.js

@@ -57,13 +57,15 @@ Coverage.CoverageModel = class extends SDK.SDKModel {
   /**
    * @return {!Promise<!Array<!Coverage.CoverageInfo>>}
    */
-  stop() {
-    const pollPromise = this.poll();
+  async stop() {
+    const result = await this.poll();
+    const promises = [];
     if (this._cpuProfilerModel)
-      this._cpuProfilerModel.stopPreciseCoverage();
+      promises.push(this._cpuProfilerModel.stopPreciseCoverage());
     if (this._cssModel)
-      this._cssModel.stopCoverage();
-    return pollPromise;
+      promises.push(this._cssModel.stopCoverage());
+    await Promise.all(promises);
+    return result;
   }
 
   reset() {

third_party/blink/renderer/devtools/front_end/sdk/Target.js

@@ -200,29 +200,25 @@ SDK.Target = class extends Protocol.TargetBase {
   /**
    * @return {!Promise}
    */
-  suspend() {
+  async suspend() {
     if (this._isSuspended)
       return Promise.resolve();
     this._isSuspended = true;
 
-    const promises = [];
-    for (const model of this.models().values())
-      promises.push(model.suspendModel());
-    return Promise.all(promises);
+    await Promise.all(Array.from(this.models().values(), m => m.preSuspendModel()));
+    await Promise.all(Array.from(this.models().values(), m => m.suspendModel()));
   }
 
   /**
    * @return {!Promise}
    */
-  resume() {
+  async resume() {
     if (!this._isSuspended)
       return Promise.resolve();
     this._isSuspended = false;
 
-    const promises = [];
-    for (const model of this.models().values())
-      promises.push(model.resumeModel());
-    return Promise.all(promises);
+    await Promise.all(Array.from(this.models().values(), m => m.resumeModel()));
+    await Promise.all(Array.from(this.models().values(), m => m.postResumeModel()));
   }
 
   /**
@@ -286,6 +282,15 @@ SDK.SDKModel = class extends Common.Object {
     return this._target;
   }
 
+  /**
+   * Override this method to perform tasks that are required to suspend the
+   * model and that still need other models in an unsuspended state.
+   * @return {!Promise}
+   */
+  preSuspendModel() {
+    return Promise.resolve();
+  }
+
   /**
    * @return {!Promise}
    */
@@ -300,6 +305,15 @@ SDK.SDKModel = class extends Common.Object {
     return Promise.resolve();
   }
 
+  /**
+   * Override this method to perform tasks that are required to after resuming
+   * the model and that require all models already in an unsuspended state.
+   * @return {!Promise}
+   */
+  postResumeModel() {
+    return Promise.resolve();
+  }
+
   dispose() {
   }
 };

third_party/blink/web_tests/http/tests/devtools/service-workers/service-worker-agents.js

@@ -30,11 +30,11 @@
   ApplicationTestRunner.waitForServiceWorker(step1);
   ApplicationTestRunner.registerServiceWorker(scriptURL, scope);
 
-  function step1(target) {
+  async function step1(target) {
     TestRunner.addResult('Suspending targets.');
-    SDK.targetManager.suspendAllTargets();
+    await SDK.targetManager.suspendAllTargets();
     TestRunner.addResult('Resuming targets.');
-    SDK.targetManager.resumeAllTargets();
+    await SDK.targetManager.resumeAllTargets();
     TestRunner.completeTest();
   }