Change kMaxSecondsToWaitForNetworkProcess to 1 second on ChromeOS.

This should reduce the number of shutdown hangs we're seeing with the
network service enabled. According to UMA, ~99.9% of all shutdowns
complete within 1s on ChromeOS.

Bug: 963512
Change-Id: Iec10ca59349be9d6fbbe2d1294f4aaf585711d3c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1613121Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Commit-Queue: Robbie McElrath <rmcelrath@chromium.org>
Cr-Commit-Position: refs/heads/master@{#659980}

content/browser/browser_process_sub_thread.cc

@@ -197,6 +197,10 @@ void BrowserProcessSubThread::IOThreadCleanUp() {
 #if BUILDFLAG(CLANG_COVERAGE)
       // On coverage build, browser_tests runs 10x slower.
       const int kMaxSecondsToWaitForNetworkProcess = 100;
+#elif defined(OS_CHROMEOS)
+      // ChromeOS will kill the browser process if it doesn't shut down within
+      // 3 seconds, so make sure we wait for less than that.
+      const int kMaxSecondsToWaitForNetworkProcess = 1;
 #else
       const int kMaxSecondsToWaitForNetworkProcess = 10;
 #endif