Move telemetry/core/timeline and timeline_data to telemetry/timeline.

tools/telemetry/telemetry/timeline/empty_timeline_data_importer_unittest.py

 # Copyright 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.
 
 import unittest
 
-from telemetry.core.timeline import empty_timeline_data_importer
-from telemetry.core.backends.chrome import tracing_timeline_data
+from telemetry.timeline import empty_timeline_data_importer
+from telemetry.timeline import tracing_timeline_data
 
 
 class EmptyTimelineDataImporterTest(unittest.TestCase):
   def testCanImportEmptyTimelineData(self):
     # We can import empty lists and empty string wrapped in subclasses of
     # TimelineData
     self.assertTrue(
         empty_timeline_data_importer.EmptyTimelineDataImporter.CanImport(
             tracing_timeline_data.TracingTimelineData([])))
     self.assertTrue(
         empty_timeline_data_importer.EmptyTimelineDataImporter.CanImport(
             tracing_timeline_data.TracingTimelineData('')))
 
   def testCannotImportNonEmptyTimelineData(self):
     # We can't import non-empty TimelineData objects
     self.assertFalse(
         empty_timeline_data_importer.EmptyTimelineDataImporter.CanImport(
             tracing_timeline_data.TracingTimelineData([1,2,3])))
 
   def testCannotImportEmptyRawData(self):
     # We can't import raw data (not wrapped in a TimelineData object)
     self.assertFalse(
         empty_timeline_data_importer.EmptyTimelineDataImporter.CanImport([]))
     self.assertFalse(
         empty_timeline_data_importer.EmptyTimelineDataImporter.CanImport(''))