Reland: [Telemetry] Fix a flake in android browser finder.

tools/telemetry/telemetry/core/backends/chrome/android_browser_finder.py

Index: tools/telemetry/telemetry/core/backends/chrome/android_browser_finder.py
diff --git a/tools/telemetry/telemetry/core/backends/chrome/android_browser_finder.py b/tools/telemetry/telemetry/core/backends/chrome/android_browser_finder.py
index f0a5ae53e4fac7ee0ed366b63671f7474d5ecd84..3ad05640df7d1079712ace49146a2fa9966a590a 100644
--- a/tools/telemetry/telemetry/core/backends/chrome/android_browser_finder.py
+++ b/tools/telemetry/telemetry/core/backends/chrome/android_browser_finder.py
@@ -19,6 +19,11 @@ from telemetry.core.backends import adb_commands
 from telemetry.core.backends.chrome import android_browser_backend
 from telemetry.core.platform import android_platform_backend
 
+try:
+  import psutil  # pylint: disable=F0401
+except ImportError:
+  psutil = None
+
 
 CHROME_PACKAGE_NAMES = {
   'android-content-shell':
@@ -207,19 +212,18 @@ def FindAllAvailableBrowsers(finder_options, logging=real_logging):
     # Ignore result.
     adb.EnableAdbRoot()
 
-  if sys.platform.startswith('linux'):
-    # Host side workaround for crbug.com/268450 (adb instability)
+  if psutil:
+    # Host side workaround for crbug.com/268450 (adb instability).
     # The adb server has a race which is mitigated by binding to a single core.
-    import psutil  # pylint: disable=F0401
-    pids  = [p.pid for p in psutil.process_iter() if 'adb' in p.name]
-    with open(os.devnull, 'w') as devnull:
-      for pid in pids:
-        ret = subprocess.call(['taskset', '-p', '-c', '0', str(pid)],
-                              stdout=subprocess.PIPE,
-                              stderr=subprocess.PIPE,
-                              stdin=devnull)
-        if ret:
-          logging.warn('Failed to taskset %d (%s)', pid, ret)
+    for proc in psutil.process_iter():
+      try:
+        if 'adb' in proc.name:
+          if hasattr(proc, 'cpu_affinity'):
+            proc.cpu_affinity([0])      # New versions of psutil.
+          else:
+            proc.set_cpu_affinity([0])  # Older versions.
+      except (psutil.NoSuchProcess, psutil.AccessDenied):
+        logging.warn('Failed to set adb process CPU affinity')
 
   if not os.environ.get('BUILDBOT_BUILDERNAME'):
     # Killing adbd before running tests has proven to make them less likely to