Refactor all video related processing to its own class

tools/perf/metrics/speedindex_unittest.py

Index: tools/perf/metrics/speedindex_unittest.py
diff --git a/tools/perf/metrics/speedindex_unittest.py b/tools/perf/metrics/speedindex_unittest.py
index c586bf9f735417f19966d36bc586097e5d83b89d..ee47ac01d87ec9a87a854953971f7ef151b7eac6 100644
--- a/tools/perf/metrics/speedindex_unittest.py
+++ b/tools/perf/metrics/speedindex_unittest.py
@@ -36,6 +36,15 @@ class FakeTimelineModel(object):
     return self._events
 
 
+class FakeVideo(object):
+
+  def __init__(self, frames):
+    self._frames = frames
+
+  def GetVideoFrameIter(self):
+    for frame in self._frames:
+      yield frame
+
 class FakeBitmap(object):
 
   def __init__(self, r, g, b):
@@ -51,7 +60,7 @@ class FakeTab(object):
   def __init__(self, video_capture_result=None):
     self._timeline_model = FakeTimelineModel()
     self._javascript_result = None
-    self._video_capture_result = video_capture_result
+    self._video_capture_result = FakeVideo(video_capture_result)
 
   @property
   def timeline_model(self):