Don't report exit funnels for live processes.

components/browser_watcher/watcher_metrics_provider_win_unittest.cc

 // Copyright (c) 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/browser_watcher/watcher_metrics_provider_win.h"
 
 #include <cstdlib>
 
 #include "base/process/process_handle.h"
 #include "base/strings/string16.h"
@@ skipping 120 matching lines @@
 
   // Make sure the subkey is deleted on reporting.
   base::win::RegistryKeyIterator it(HKEY_CURRENT_USER, kRegistryPath);
   ASSERT_EQ(it.SubkeyCount(), 0);
 }
 
 TEST_F(WatcherMetricsProviderWinTest, ReadsExitFunnelWrites) {
   // Test that the metrics provider picks up the writes from
   ExitFunnel funnel;
 
+  // Events against our own process should not get reported.
   ASSERT_TRUE(funnel.Init(kRegistryPath, base::GetCurrentProcessHandle()));
+  ASSERT_TRUE(funnel.RecordEvent(L"Forgetaboutit"));
+
+  // Reset the funnel to a pseudo process. The PID 4 is the system process,
+  // which tests can hopefully never open.
+  ASSERT_TRUE(funnel.InitImpl(kRegistryPath, 4, base::Time::Now()));

[erikwright (departed), 2014/12/19 20:03:38]

I don't understand the purpose of this. Is it to trick the code that does the
verification of the process being dead?

It seems like it wouldn't be too big a deal to launch a child test process and
use a named mutex to prevent it from exiting. Then you would have a real test
without exposing an awkward "for testing" init method and without relying on
intimate knowledge of how the code detects live processes.

 
   // Each named event can only exist in a single copy.
   ASSERT_TRUE(funnel.RecordEvent(L"One"));
   ASSERT_TRUE(funnel.RecordEvent(L"One"));
   ASSERT_TRUE(funnel.RecordEvent(L"One"));
   ASSERT_TRUE(funnel.RecordEvent(L"Two"));
   ASSERT_TRUE(funnel.RecordEvent(L"Three"));
 
   WatcherMetricsProviderWin provider(kRegistryPath);
 
   provider.ProvideStabilityMetrics(NULL);
   histogram_tester_.ExpectTotalCount("Stability.ExitFunnel.One", 1);
   histogram_tester_.ExpectTotalCount("Stability.ExitFunnel.Two", 1);
   histogram_tester_.ExpectTotalCount("Stability.ExitFunnel.Three", 1);
 
-  // Make sure the subkey has been deleted on reporting.
+  // Make sure the subkey for the pseudo process has been deleted on reporting.
   base::win::RegistryKeyIterator it(HKEY_CURRENT_USER, kRegistryPath);
-  ASSERT_EQ(it.SubkeyCount(), 0);
+  ASSERT_EQ(it.SubkeyCount(), 1);
 }
 
 }  // namespace browser_watcher