[Gardening] Move imports and DriverArgs to top

Author: palimondo

benchmark/scripts/run_smoke_bench

@@ -32,9 +32,29 @@ import sys
 
 from compare_perf_tests import LogParser, create_report
 
+from imp import load_source
+# import Benchmark_Driver  # doesn't work because it misses '.py' extension
+Benchmark_Driver = load_source(
+    'Benchmark_Driver', os.path.join(os.path.dirname(
+        os.path.abspath(__file__)), 'Benchmark_Driver'))
+# from Benchmark_Driver import BenchmarkDriver, BenchmarkDoctor, ...
+BenchmarkDriver = Benchmark_Driver.BenchmarkDriver
+BenchmarkDoctor = Benchmark_Driver.BenchmarkDoctor
+MarkdownReportHandler = Benchmark_Driver.MarkdownReportHandler
+
 VERBOSE = False
 
 
+class DriverArgs(object):
+    """Arguments for BenchmarkDriver."""
+    def __init__(self, tests, optimization='O'):
+        """Initialize with path to the build-dir and optimization level."""
+        self.benchmarks = None
+        self.filters = None
+        self.tests = os.path.join(tests, 'bin')
+        self.optimization = optimization
+
+
 def log(msg):
     print(msg)
     sys.stdout.flush()
@@ -332,25 +352,7 @@ performance team (@eeckstein).
     return text
 
 
-class DriverArgs(object):
-    def __init__(self, tests):
-        self.benchmarks = None
-        self.filters = None
-        self.tests = os.path.join(tests, 'bin')
-        self.optimization = 'O'
-
-
 def check_added(args, output_file=None):
-    from imp import load_source
-    # import Benchmark_Driver  # doesn't work because it misses '.py' extension
-    Benchmark_Driver = load_source(
-        'Benchmark_Driver', os.path.join(os.path.dirname(
-            os.path.abspath(__file__)), 'Benchmark_Driver'))
-    # from Benchmark_Driver import BenchmarkDriver, BenchmarkDoctor
-    BenchmarkDriver = Benchmark_Driver.BenchmarkDriver
-    BenchmarkDoctor = Benchmark_Driver.BenchmarkDoctor
-    MarkdownReportHandler = Benchmark_Driver.MarkdownReportHandler
-
     old = BenchmarkDriver(DriverArgs(args.oldbuilddir[0]))
     new = BenchmarkDriver(DriverArgs(args.newbuilddir[0]))
     added = set(new.tests).difference(set(old.tests))