Add unit-test for SharedSampler handling of zero-thread processes.

chrome/test/BUILD.gn

Index: chrome/test/BUILD.gn
diff --git a/chrome/test/BUILD.gn b/chrome/test/BUILD.gn
index c6378c036acf74939e144305077c68f511a09e93..bd5102ce844f9a90bb902a9947ec55257b6ffc8f 100644
--- a/chrome/test/BUILD.gn
+++ b/chrome/test/BUILD.gn
@@ -3631,7 +3631,7 @@ test("unit_tests") {
       "../browser/sync/sync_ui_util_unittest.cc",  # Sync setup uses native ui.
       "../browser/task_manager/providers/browser_process_task_unittest.cc",
       "../browser/task_manager/providers/child_process_task_unittest.cc",
-      "../browser/task_manager/sampling/shared_sampler_unittest_win.cc",

[stanisc, 2017/01/30 21:51:14]

Iteresting! It looks like both patterns are used but _win_unittest.cc if far
more common.

[Wez, 2017/01/31 03:36:24]

Yes, I thought I'd change this since it seems more logical, but I notice a load
of other tests use the other form.

+      "../browser/task_manager/sampling/shared_sampler_win_unittest.cc",
       "../browser/task_manager/sampling/task_manager_impl_unittest.cc",
       "../browser/task_manager/task_manager_observer_unittest.cc",
       "../browser/task_manager/test_task_manager.cc",