[telemetry] Simplify PRESUBMIT.py path logic and remove import-error disables.

Before we added paths to PyLint's PYTHONPATH by temporarily modifying sys.path, but GetPyLint() also takes extra_paths_list as a parameter and modifies PYTHONPATH for us.

BUG=

Review URL: https://codereview.chromium.org/1235423003

Cr-Commit-Position: refs/heads/master@{#338995}

22 files changed, 68 insertions, 66 deletions

diff --git a/tools/telemetry/PRESUBMIT.py b/tools/telemetry/PRESUBMIT.py
index da4388d..5961c94 100644
--- a/tools/telemetry/PRESUBMIT.py
+++ b/tools/telemetry/PRESUBMIT.py
@@ -1,8 +1,6 @@
 # Copyright 2012 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.
-import os
-import sys
 
 
 def _CommonChecks(input_api, output_api):
@@ -11,42 +9,45 @@ def _CommonChecks(input_api, output_api):
   # TODO(nduca): This should call update_docs.IsUpdateDocsNeeded().
   # Disabled due to crbug.com/255326.
   if False:
-    update_docs_path = os.path.join(
+    update_docs_path = input_api.os_path.join(
       input_api.PresubmitLocalPath(), 'update_docs')
-    assert os.path.exists(update_docs_path)
+    assert input_api.os_path.exists(update_docs_path)
     results.append(output_api.PresubmitError(
       'Docs are stale. Please run:\n' +
-      '$ %s' % os.path.abspath(update_docs_path)))
+      '$ %s' % input_api.os_path.abspath(update_docs_path)))
 
   pylint_checks = input_api.canned_checks.GetPylint(
-    input_api, output_api, black_list=[], pylintrc='pylintrc')
+    input_api, output_api, extra_paths_list=_GetPathsToPrepend(input_api),
+    pylintrc='pylintrc')
 
   results.extend(input_api.RunTests(pylint_checks))
   return results
 
-def GetPathsToPrepend(input_api):
-  return [input_api.PresubmitLocalPath(),
-          os.path.join(input_api.PresubmitLocalPath(), 'third_party', 'typ')]
 
-def RunWithPrependedPath(prepended_path, fn, *args):
-  old_path = sys.path
+def _GetPathsToPrepend(input_api):
+  telemetry_dir = input_api.PresubmitLocalPath()
+  chromium_src_dir = input_api.os_path.join(telemetry_dir, '..', '..')
+  return [
+      telemetry_dir,
+      input_api.os_path.join(telemetry_dir, 'third_party', 'mock'),
+      input_api.os_path.join(telemetry_dir, 'third_party', 'typ'),
+      input_api.os_path.join(telemetry_dir, 'third_party', 'websocket-client'),
+
+      input_api.os_path.join(chromium_src_dir, 'build', 'android'),
+      input_api.os_path.join(
+          chromium_src_dir, 'third_party', 'py_trace_event', 'src'),
+      input_api.os_path.join(chromium_src_dir, 'third_party', 'trace-viewer'),
+      input_api.os_path.join(chromium_src_dir, 'third_party', 'webpagereplay'),
+  ]
 
-  try:
-    sys.path = prepended_path + old_path
-    return fn(*args)
-  finally:
-    sys.path = old_path
 
 def CheckChangeOnUpload(input_api, output_api):
-  def go():
-    results = []
-    results.extend(_CommonChecks(input_api, output_api))
-    return results
-  return RunWithPrependedPath(GetPathsToPrepend(input_api), go)
+  results = []
+  results.extend(_CommonChecks(input_api, output_api))
+  return results
+
 
 def CheckChangeOnCommit(input_api, output_api):
-  def go():
-    results = []
-    results.extend(_CommonChecks(input_api, output_api))
-    return results
-  return RunWithPrependedPath(GetPathsToPrepend(input_api), go)
+  results = []
+  results.extend(_CommonChecks(input_api, output_api))
+  return results
diff --git a/tools/telemetry/telemetry/core/platform/android_device.py b/tools/telemetry/telemetry/core/platform/android_device.py
index 105700f..2917ef0 100644
--- a/tools/telemetry/telemetry/core/platform/android_device.py
+++ b/tools/telemetry/telemetry/core/platform/android_device.py
@@ -11,9 +11,9 @@ from telemetry.core.platform.profiler import monsoon
 from telemetry.core import util
 
 util.AddDirToPythonPath(util.GetChromiumSrcDir(), 'build', 'android')
-from pylib import constants # pylint: disable=import-error
-from pylib.device import device_errors # pylint: disable=import-error
-from pylib.device import device_utils # pylint: disable=import-error
+from pylib import constants
+from pylib.device import device_errors
+from pylib.device import device_utils
 
 
 class AndroidDevice(device.Device):
diff --git a/tools/telemetry/telemetry/core/platform/android_device_unittest.py b/tools/telemetry/telemetry/core/platform/android_device_unittest.py
index 9cddabf..b0e3429 100644
--- a/tools/telemetry/telemetry/core/platform/android_device_unittest.py
+++ b/tools/telemetry/telemetry/core/platform/android_device_unittest.py
@@ -10,10 +10,10 @@ from telemetry.internal.browser import browser_options
 from telemetry.testing import system_stub
 
 util.AddDirToPythonPath(util.GetChromiumSrcDir(), 'build', 'android')
-from pylib.device import device_utils # pylint: disable=import-error
+from pylib.device import device_utils
 
 util.AddDirToPythonPath(util.GetTelemetryDir(), 'third_party', 'mock')
-import mock # pylint: disable=import-error
+import mock
 
 
 class _BaseAndroidDeviceTest(unittest.TestCase):
diff --git a/tools/telemetry/telemetry/core/platform/android_platform_backend.py b/tools/telemetry/telemetry/core/platform/android_platform_backend.py
index 8895378..28ebb6d 100644
--- a/tools/telemetry/telemetry/core/platform/android_platform_backend.py
+++ b/tools/telemetry/telemetry/core/platform/android_platform_backend.py
@@ -32,23 +32,23 @@ from telemetry.internal.util import external_modules
 psutil = external_modules.ImportOptionalModule('psutil')
 util.AddDirToPythonPath(util.GetChromiumSrcDir(),
                         'third_party', 'webpagereplay')
-import adb_install_cert  # pylint: disable=import-error
-import certutils  # pylint: disable=import-error
-import platformsettings  # pylint: disable=import-error
+import adb_install_cert
+import certutils
+import platformsettings
 
 # Get build/android scripts into our path.
 util.AddDirToPythonPath(util.GetChromiumSrcDir(), 'build', 'android')
-from pylib import constants  # pylint: disable=import-error
-from pylib import screenshot  # pylint: disable=import-error
-from pylib.device import battery_utils  # pylint: disable=import-error
-from pylib.device import device_errors  # pylint: disable=import-error
-from pylib.device import device_utils  # pylint: disable=import-error
-from pylib.perf import cache_control  # pylint: disable=import-error
-from pylib.perf import perf_control  # pylint: disable=import-error
-from pylib.perf import thermal_throttle  # pylint: disable=import-error
+from pylib import constants
+from pylib import screenshot
+from pylib.device import battery_utils
+from pylib.device import device_errors
+from pylib.device import device_utils
+from pylib.perf import cache_control
+from pylib.perf import perf_control
+from pylib.perf import thermal_throttle
 
 try:
-  from pylib.perf import surface_stats_collector  # pylint: disable=import-error
+  from pylib.perf import surface_stats_collector
 except Exception:
   surface_stats_collector = None
 
diff --git a/tools/telemetry/telemetry/core/platform/android_platform_backend_unittest.py b/tools/telemetry/telemetry/core/platform/android_platform_backend_unittest.py
index 7af3c84..3c6cc89 100644
--- a/tools/telemetry/telemetry/core/platform/android_platform_backend_unittest.py
+++ b/tools/telemetry/telemetry/core/platform/android_platform_backend_unittest.py
@@ -12,10 +12,10 @@ from telemetry.testing import options_for_unittests
 from telemetry.testing import system_stub
 
 util.AddDirToPythonPath(util.GetTelemetryDir(), 'third_party', 'mock')
-import mock  # pylint: disable=import-error
+import mock
 util.AddDirToPythonPath(util.GetChromiumSrcDir(), 'build', 'android')
-from pylib.device import battery_utils  # pylint: disable=import-error
-from pylib.device import device_utils  # pylint: disable=import-error
+from pylib.device import battery_utils
+from pylib.device import device_utils
 
 class AndroidPlatformBackendTest(unittest.TestCase):
   def setUp(self):
diff --git a/tools/telemetry/telemetry/core/platform/linux_based_platform_backend_unittest.py b/tools/telemetry/telemetry/core/platform/linux_based_platform_backend_unittest.py
index 66c25bf..eaa36f4 100644
--- a/tools/telemetry/telemetry/core/platform/linux_based_platform_backend_unittest.py
+++ b/tools/telemetry/telemetry/core/platform/linux_based_platform_backend_unittest.py
@@ -10,7 +10,7 @@ from telemetry.core.platform import linux_based_platform_backend
 from telemetry.core import util
 
 util.AddDirToPythonPath(util.GetTelemetryDir(), 'third_party', 'mock')
-import mock  # pylint: disable=import-error
+import mock
 
 
 class TestBackend(linux_based_platform_backend.LinuxBasedPlatformBackend):
diff --git a/tools/telemetry/telemetry/core/platform/linux_platform_backend_unittest.py b/tools/telemetry/telemetry/core/platform/linux_platform_backend_unittest.py
index 8e714e3..1059285 100644
--- a/tools/telemetry/telemetry/core/platform/linux_platform_backend_unittest.py
+++ b/tools/telemetry/telemetry/core/platform/linux_platform_backend_unittest.py
@@ -10,7 +10,7 @@ from telemetry.core import util
 from telemetry import decorators
 
 util.AddDirToPythonPath(util.GetTelemetryDir(), 'third_party', 'mock')
-import mock  # pylint:disable=import-error
+import mock
 
 
 class LinuxPlatformBackendTest(unittest.TestCase):
diff --git a/tools/telemetry/telemetry/decorators_unittest.py b/tools/telemetry/telemetry/decorators_unittest.py
index d76f83d..7aecc84 100644
--- a/tools/telemetry/telemetry/decorators_unittest.py
+++ b/tools/telemetry/telemetry/decorators_unittest.py
@@ -8,7 +8,7 @@ from telemetry import decorators
 from telemetry.core import util
 
 util.AddDirToPythonPath(util.GetTelemetryDir(), 'third_party', 'mock')
-import mock  # pylint:disable=import-error
+import mock
 
 
 class FakePlatform(object):
diff --git a/tools/telemetry/telemetry/internal/actions/action_runner_unittest.py b/tools/telemetry/telemetry/internal/actions/action_runner_unittest.py
index e4649b5..5962e90 100644
--- a/tools/telemetry/telemetry/internal/actions/action_runner_unittest.py
+++ b/tools/telemetry/telemetry/internal/actions/action_runner_unittest.py
@@ -15,7 +15,7 @@ from telemetry.timeline import tracing_options
 from telemetry.web_perf import timeline_interaction_record as tir_module
 
 util.AddDirToPythonPath(util.GetTelemetryDir(), 'third_party', 'mock')
-import mock  # pylint:disable=import-error
+import mock
 
 
 class ActionRunnerInteractionTest(tab_test_case.TabTestCase):
diff --git a/tools/telemetry/telemetry/internal/app/android_app_unittest.py b/tools/telemetry/telemetry/internal/app/android_app_unittest.py
index ab8ad36..db09330 100644
--- a/tools/telemetry/telemetry/internal/app/android_app_unittest.py
+++ b/tools/telemetry/telemetry/internal/app/android_app_unittest.py
@@ -14,7 +14,7 @@ from telemetry.internal.backends import android_app_backend
 from telemetry.testing import options_for_unittests
 
 util.AddDirToPythonPath(util.GetChromiumSrcDir(), 'build', 'android')
-from pylib.device import intent  # pylint: disable=import-error
+from pylib.device import intent
 
 
 class AndroidAppTest(unittest.TestCase):
diff --git a/tools/telemetry/telemetry/internal/app/android_process.py b/tools/telemetry/telemetry/internal/app/android_process.py
index 03829e7..959719b 100644
--- a/tools/telemetry/telemetry/internal/app/android_process.py
+++ b/tools/telemetry/telemetry/internal/app/android_process.py
@@ -8,7 +8,7 @@ from telemetry.internal.browser import web_contents
 
 util.AddDirToPythonPath(util.GetChromiumSrcDir(), 'build', 'android')
 try:
-  from pylib import ports  # pylint: disable=import-error
+  from pylib import ports
 except ImportError:
   ports = None
 
diff --git a/tools/telemetry/telemetry/internal/backends/android_command_line_backend_unittest.py b/tools/telemetry/telemetry/internal/backends/android_command_line_backend_unittest.py
index a19a868..5d6138f 100644
--- a/tools/telemetry/telemetry/internal/backends/android_command_line_backend_unittest.py
+++ b/tools/telemetry/telemetry/internal/backends/android_command_line_backend_unittest.py
@@ -11,7 +11,7 @@ from telemetry.internal.backends import android_command_line_backend
 from telemetry.testing import options_for_unittests
 
 util.AddDirToPythonPath(util.GetChromiumSrcDir(), 'build', 'android')
-from pylib.device import device_utils # pylint: disable=import-error
+from pylib.device import device_utils
 
 
 class _MockBackendSettings(object):
diff --git a/tools/telemetry/telemetry/internal/backends/chrome/android_browser_backend.py b/tools/telemetry/telemetry/internal/backends/chrome/android_browser_backend.py
index 698b300..d61d95f 100644
--- a/tools/telemetry/telemetry/internal/backends/chrome/android_browser_backend.py
+++ b/tools/telemetry/telemetry/internal/backends/chrome/android_browser_backend.py
@@ -16,10 +16,10 @@ from telemetry.internal import forwarders
 
 util.AddDirToPythonPath(util.GetChromiumSrcDir(), 'build', 'android')
 try:
-  from pylib import ports # pylint: disable=import-error
+  from pylib import ports
 except ImportError:
   ports = None
-from pylib.device import intent  # pylint: disable=import-error
+from pylib.device import intent
 
 
 class AndroidBrowserBackend(chrome_browser_backend.ChromeBrowserBackend):
diff --git a/tools/telemetry/telemetry/internal/backends/chrome/android_browser_finder.py b/tools/telemetry/telemetry/internal/backends/chrome/android_browser_finder.py
index 245ba59..a36acaf 100644
--- a/tools/telemetry/telemetry/internal/backends/chrome/android_browser_finder.py
+++ b/tools/telemetry/telemetry/internal/backends/chrome/android_browser_finder.py
@@ -18,7 +18,7 @@ from telemetry.internal.browser import browser
 from telemetry.internal.browser import possible_browser
 
 util.AddDirToPythonPath(util.GetChromiumSrcDir(), 'build', 'android')
-from pylib.utils import apk_helper # pylint: disable=import-error
+from pylib.utils import apk_helper
 
 
 CHROME_PACKAGE_NAMES = {
diff --git a/tools/telemetry/telemetry/internal/backends/chrome/android_browser_finder_unittest.py b/tools/telemetry/telemetry/internal/backends/chrome/android_browser_finder_unittest.py
index 7e04024..9b7dbe9 100644
--- a/tools/telemetry/telemetry/internal/backends/chrome/android_browser_finder_unittest.py
+++ b/tools/telemetry/telemetry/internal/backends/chrome/android_browser_finder_unittest.py
@@ -10,7 +10,7 @@ from telemetry.internal.browser import browser_options
 from telemetry.testing import system_stub
 
 util.AddDirToPythonPath(util.GetTelemetryDir(), 'third_party', 'mock')
-import mock # pylint: disable=import-error
+import mock
 
 
 class FakeAndroidPlatform(object):
diff --git a/tools/telemetry/telemetry/internal/backends/chrome_inspector/tracing_backend_unittest.py b/tools/telemetry/telemetry/internal/backends/chrome_inspector/tracing_backend_unittest.py
index 073c118..41da978 100644
--- a/tools/telemetry/telemetry/internal/backends/chrome_inspector/tracing_backend_unittest.py
+++ b/tools/telemetry/telemetry/internal/backends/chrome_inspector/tracing_backend_unittest.py
@@ -14,7 +14,7 @@ from telemetry.timeline import tracing_category_filter
 from telemetry.timeline import tracing_options
 
 util.AddDirToPythonPath(util.GetTelemetryDir(), 'third_party', 'mock')
-import mock  # pylint:disable=import-error
+import mock
 
 
 class FakeInspectorWebsocket(object):
diff --git a/tools/telemetry/telemetry/internal/backends/chrome_inspector/websocket.py b/tools/telemetry/telemetry/internal/backends/chrome_inspector/websocket.py
index f8682fd..9da12e9 100644
--- a/tools/telemetry/telemetry/internal/backends/chrome_inspector/websocket.py
+++ b/tools/telemetry/telemetry/internal/backends/chrome_inspector/websocket.py
@@ -9,7 +9,7 @@ from telemetry.core import util
 
 util.AddDirToPythonPath(
     util.GetTelemetryDir(), 'third_party', 'websocket-client')
-# pylint: disable=import-error, unused-import
+# pylint: disable=unused-import
 from websocket import create_connection as _create_connection
 from websocket import WebSocketException
 from websocket import WebSocketTimeoutException
diff --git a/tools/telemetry/telemetry/internal/forwarders/android_forwarder.py b/tools/telemetry/telemetry/internal/forwarders/android_forwarder.py
index 2a599e4..9fcc743 100644
--- a/tools/telemetry/telemetry/internal/forwarders/android_forwarder.py
+++ b/tools/telemetry/telemetry/internal/forwarders/android_forwarder.py
@@ -17,12 +17,12 @@ from telemetry.internal import forwarders
 
 util.AddDirToPythonPath(util.GetChromiumSrcDir(), 'build', 'android')
 try:
-  from pylib import forwarder  # pylint: disable=import-error
+  from pylib import forwarder
 except ImportError:
   forwarder = None
 
-from pylib.device import device_errors  # pylint: disable=import-error
-from pylib.device import device_utils  # pylint: disable=import-error
+from pylib.device import device_errors
+from pylib.device import device_utils
 
 
 class AndroidForwarderFactory(forwarders.ForwarderFactory):
diff --git a/tools/telemetry/telemetry/internal/util/py_trace.py b/tools/telemetry/telemetry/internal/util/py_trace.py
index 54d2afc..01affc8 100644
--- a/tools/telemetry/telemetry/internal/util/py_trace.py
+++ b/tools/telemetry/telemetry/internal/util/py_trace.py
@@ -7,4 +7,5 @@ from telemetry.core import util
 
 util.AddDirToPythonPath(util.GetChromiumSrcDir(),
                         'third_party', 'py_trace_event', 'src')
-from trace_event import *  # pylint: disable=import-error, wildcard-import
+# pylint: disable=wildcard-import, unused-wildcard-import
+from trace_event import *
diff --git a/tools/telemetry/telemetry/timeline/memory_dump_event_unittest.py b/tools/telemetry/telemetry/timeline/memory_dump_event_unittest.py
index efa48bf..852d8bd 100644
--- a/tools/telemetry/telemetry/timeline/memory_dump_event_unittest.py
+++ b/tools/telemetry/telemetry/timeline/memory_dump_event_unittest.py
@@ -8,7 +8,7 @@ from telemetry.core import util
 from telemetry.timeline import memory_dump_event
 
 util.AddDirToPythonPath(util.GetTelemetryDir(), 'third_party', 'mock')
-import mock # pylint: disable=import-error
+import mock
 
 
 def TestProcessDumpEvent(dump_id='123456ABCDEF', pid=1234, start=0, mmaps=None,
diff --git a/tools/telemetry/telemetry/value/trace.py b/tools/telemetry/telemetry/value/trace.py
index 3ea2b5d..b8e068b 100644
--- a/tools/telemetry/telemetry/value/trace.py
+++ b/tools/telemetry/telemetry/value/trace.py
@@ -21,7 +21,7 @@ from telemetry import value as value_module
 util.AddDirToPythonPath(
     util.GetChromiumSrcDir(), 'third_party', 'trace-viewer')
 
-from tracing.build import trace2html  # pylint:disable=import-error
+from tracing.build import trace2html
 
 class TraceValue(value_module.Value):
   def __init__(self, page, trace_data, important=False, description=None):
diff --git a/tools/telemetry/telemetry/web_perf/metrics/memory_timeline_unittest.py b/tools/telemetry/telemetry/web_perf/metrics/memory_timeline_unittest.py
index 9135472..01c54a1 100644
--- a/tools/telemetry/telemetry/web_perf/metrics/memory_timeline_unittest.py
+++ b/tools/telemetry/telemetry/web_perf/metrics/memory_timeline_unittest.py
@@ -13,7 +13,7 @@ from telemetry.web_perf.metrics import memory_timeline
 from telemetry.web_perf import timeline_interaction_record
 
 util.AddDirToPythonPath(util.GetTelemetryDir(), 'third_party', 'mock')
-import mock # pylint: disable=import-error
+import mock
 
 
 def MockProcessDumpEvent(dump_id, name, start, memory_usage):