adb_profile_chrome: Add perf profiler

build/android/chrome_profiler/postprocessor_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.
+
+from chrome_profiler import postprocessor
+
+import json
+import tempfile
+import unittest
+
+
+class PostprocessorTest(unittest.TestCase):
+  def testJsonTraceMerging(self):
+    t1 = {'traceEvents': [{'ts': 123, 'ph': 'b'}]}
+    t2 = {'traceEvents': [], 'stackFrames': ['blah']}
+
+    with tempfile.NamedTemporaryFile(delete=False) as f1:
+      with tempfile.NamedTemporaryFile(delete=False) as f2:

[bulach, 2014/06/04 10:34:12]

why delete=False? the with would only close them at the end, so perhaps just
keep the default delete=True? ...or some comment :)

[Sami, 2014/06/04 15:16:59]

Both of these files get deleted during merging, and NamedTemporaryFile doesn't
like if you delete the file before it gets to it. I've added a comment to make
this clearer.

+        f1.write(json.dumps(t1))
+        f2.write(json.dumps(t2))
+        f1.flush()
+        f2.flush()
+
+        with tempfile.NamedTemporaryFile() as output:
+          postprocessor.PackageTraces([f1.name, f2.name],
+                                      output.name,
+                                      compress=False,
+                                      write_json=True)
+          with open(output.name) as output:
+            output = json.load(output)
+            self.assertEquals(output['traceEvents'], t1['traceEvents'])
+            self.assertEquals(output['stackFrames'], t2['stackFrames'])