Extend base::win::ObjectWatcher to watch an event multiple times.

This is split off from https://codereview.chromium.org/1350023003/. During performance testing, it was found that it was 5x faster to watch an auto-reset event once instead of a manual-reset event every time it fired.

BUG=478251

Review URL: https://codereview.chromium.org/1366093006

Cr-Commit-Position: refs/heads/master@{#351240}

1 files changed, 6 insertions, 4 deletions

diff --git a/chrome/service/cloud_print/print_system_win.cc b/chrome/service/cloud_print/print_system_win.cc
index e4a6262..26c56263 100644
--- a/chrome/service/cloud_print/print_system_win.cc
+++ b/chrome/service/cloud_print/print_system_win.cc
@@ -68,7 +68,7 @@ class PrintSystemWatcherWin : public base::win::ObjectWatcher::Delegate {
       printer_change_.Set(FindFirstPrinterChangeNotification(
           printer_.Get(), PRINTER_CHANGE_PRINTER|PRINTER_CHANGE_JOB, 0, NULL));
       if (printer_change_.IsValid()) {
-        ret = watcher_.StartWatching(printer_change_.Get(), this);
+        ret = watcher_.StartWatchingOnce(printer_change_.Get(), this);
       }
     }
     if (!ret) {
@@ -106,7 +106,7 @@ class PrintSystemWatcherWin : public base::win::ObjectWatcher::Delegate {
         delegate_->OnJobChanged();
       }
     }
-    watcher_.StartWatching(printer_change_.Get(), this);
+    watcher_.StartWatchingOnce(printer_change_.Get(), this);
   }
 
   bool GetCurrentPrinterInfo(printing::PrinterBasicInfo* printer_info) {
@@ -361,7 +361,8 @@ class JobSpoolerWin : public PrintSystem::JobSpooler {
         delegate_->OnJobSpoolSucceeded(job_status.jobId);
       } else {
         job_progress_watcher_.StopWatching();
-        job_progress_watcher_.StartWatching(job_progress_event_.Get(), this);
+        job_progress_watcher_.StartWatchingOnce(
+            job_progress_event_.Get(), this);
       }
     }
 
@@ -483,7 +484,8 @@ class JobSpoolerWin : public PrintSystem::JobSpooler {
       if (FAILED(doc_stream->Close()))
         return false;
 
-      job_progress_watcher_.StartWatching(job_progress_event_.Get(), this);
+      job_progress_watcher_.StartWatchingOnce(
+          job_progress_event_.Get(), this);
       job_canceler.reset();
       return true;
     }