Fix CaptivePortalBrowserTest's WaitForJobs() function.

It wasn't actually waiting for |num_jobs| when NavigationLoaderOnUI
is enabled. When that feature is enabled, the function is called
directly from the UI thread, and if |ongoing_mock_requests_|
doesn't have size |num_jobs| it would return without waiting.

This was discovered by
https://chromium-review.googlesource.com/c/chromium/src/+/1688592
which will introduce a thread hop in order to perform service worker
interception before doing an outgoing network request, so WaitForJobs()
will be called before a request is added to ongoing_mock_requests_.

Bug: 824858, 978556
Change-Id: I7264f1a4f04e517694417affcd5a8d20d0f4b9b8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1689979
Commit-Queue: Matt Falkenhagen <falken@chromium.org>
Reviewed-by: Colin Blundell <blundell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#676347}

chrome/browser/captive_portal/captive_portal_browsertest.cc

@@ -762,26 +762,37 @@ class CaptivePortalBrowserTest : public InProcessBrowserTest {
 
   // Waits for exactly |num_jobs| kMockHttps* requests.
   void WaitForJobs(int num_jobs) {
-    if (!BrowserThread::CurrentlyOn(GetInterceptorThreadID())) {
+    if (BrowserThread::CurrentlyOn(GetInterceptorThreadID())) {
+      SetNumJobsToWaitForOnInterceptorThread(num_jobs);
+    } else {
       base::PostTaskWithTraits(
           FROM_HERE, {GetInterceptorThreadID()},
-          base::BindOnce(&CaptivePortalBrowserTest::WaitForJobs,
-                         base::Unretained(this), num_jobs));
-      run_loop_ = std::make_unique<base::RunLoop>();
-      run_loop_->Run();
-      return;
+          base::BindOnce(
+              &CaptivePortalBrowserTest::SetNumJobsToWaitForOnInterceptorThread,
+              base::Unretained(this), num_jobs));
     }
 
+    run_loop_ = std::make_unique<base::RunLoop>();
+    // Will be exited via QuitRunLoop() when the interceptor has received
+    // |num_jobs|.
+    run_loop_->Run();
+  }
+
+  void SetNumJobsToWaitForOnInterceptorThread(int num_jobs) {
+    DCHECK_CURRENTLY_ON(GetInterceptorThreadID());
     DCHECK(!num_jobs_to_wait_for_);
-    EXPECT_LE(static_cast<int>(ongoing_mock_requests_.size()), num_jobs);
-    if (num_jobs == static_cast<int>(ongoing_mock_requests_.size())) {
+
+    int num_ongoing_jobs = static_cast<int>(ongoing_mock_requests_.size());
+    if (num_ongoing_jobs == num_jobs) {
       base::PostTaskWithTraits(
           FROM_HERE, {BrowserThread::UI},
           base::BindOnce(&CaptivePortalBrowserTest::QuitRunLoop,
                          base::Unretained(this)));
-    } else {
-      num_jobs_to_wait_for_ = num_jobs;
+      return;
     }
+
+    EXPECT_LT(num_ongoing_jobs, num_jobs);
+    num_jobs_to_wait_for_ = num_jobs;
   }
 
   // Fails all active kMockHttps* requests with connection timeouts.
@@ -887,7 +898,7 @@ class CaptivePortalBrowserTest : public InProcessBrowserTest {
  protected:
   std::unique_ptr<content::URLLoaderInterceptor> url_loader_interceptor_;
   std::unique_ptr<base::RunLoop> run_loop_;
-  // Only accessed on the IO thread.
+  // Only accessed on the |GetInterceptorThreadID()| thread.
   int num_jobs_to_wait_for_ = 0;
   std::vector<content::URLLoaderInterceptor::RequestParams>
       ongoing_mock_requests_;