[telemetry] Catch NoAdbError when killing the adb server.

BUG=567797,568151

Review URL: https://codereview.chromium.org/1526633003

Cr-Commit-Position: refs/heads/master@{#365102}

3 files changed, 13 insertions, 5 deletions

diff --git a/build/android/devil/android/device_errors.py b/build/android/devil/android/device_errors.py
index 2fe5a80..ea14bf9 100644
--- a/build/android/devil/android/device_errors.py
+++ b/build/android/devil/android/device_errors.py
@@ -112,6 +112,6 @@ class NoDevicesError(base_error.BaseError):
 class NoAdbError(base_error.BaseError):
   """Exception for being unable to find ADB."""
 
-  def __init__(self):
+  def __init__(self, msg=None):
     super(NoAdbError, self).__init__(
-        'Unable to find adb.', is_infra_error=True)
+        msg or 'Unable to find adb.', is_infra_error=True)
diff --git a/build/android/devil/android/sdk/adb_wrapper.py b/build/android/devil/android/sdk/adb_wrapper.py
index 38db0e1..17288c2 100644
--- a/build/android/devil/android/sdk/adb_wrapper.py
+++ b/build/android/devil/android/sdk/adb_wrapper.py
@@ -115,7 +115,7 @@ class AdbWrapper(object):
           timeout_retry.CurrentTimeoutThreadGroup().GetRemainingTime())
     except OSError as e:
       if e.errno in (errno.ENOENT, errno.ENOEXEC):
-        raise device_errors.NoAdbError()
+        raise device_errors.NoAdbError(msg=str(e))
       else:
         raise
 
diff --git a/tools/telemetry/telemetry/internal/platform/android_device.py b/tools/telemetry/telemetry/internal/platform/android_device.py
index b3448b69..bcddb60 100644
--- a/tools/telemetry/telemetry/internal/platform/android_device.py
+++ b/tools/telemetry/telemetry/internal/platform/android_device.py
@@ -129,7 +129,11 @@ def GetDevice(finder_options):
 
 
 def _HasValidAdb():
-  """Returns true if adb is present."""
+  """Returns true if adb is present.
+
+  Note that this currently will return True even if the adb that's present
+  cannot run on this system.
+  """
   if os.name != 'posix' or cros_device.IsRunningOnCrOS():
     return False
 
@@ -186,6 +190,10 @@ def FindAllAvailableDevices(options):
       devices = AndroidDevice.GetAllConnectedDevices(blacklist)
   finally:
     if not devices and _HasValidAdb():
-      adb_wrapper.AdbWrapper.KillServer()
+      try:
+        adb_wrapper.AdbWrapper.KillServer()
+      except device_errors.NoAdbError as e:
+        logging.warning(
+            'adb reported as present, but NoAdbError thrown: %s', str(e))
 
   return devices