youtube_playback: Add youtube_playback workload

This is a very simple workload that just aims to allow collecting
instrumentation data on purely the video decoding aspect of Youtube.

wa/workloads/youtube_playback/__init__.py

@@ -0,0 +1,52 @@
+#    Copyright 2017 ARM Limited
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+import time
+
+from wa import Parameter, ApkWorkload
+
+
+class YoutubePlayback(ApkWorkload):
+    """
+    Simple Youtube video playback
+
+    This triggers a video streaming playback on Youtube. Unlike the more
+    featureful "youtube" workload, this performs no other action that starting
+    the video via an intent and then waiting for a certain amount of playback
+    time. This is therefore only useful when you are confident that the content
+    on the end of the provided URL is stable - that means the video should have
+    no advertisements attached.
+    """
+    name = 'youtube_playback'
+
+    package_names = ['com.google.android.youtube']
+    action = 'android.intent.action.VIEW'
+
+    parameters = [
+        Parameter('video_url', default='https://www.youtube.com/watch?v=YE7VzlLtp-4',
+                  description='URL of video to play'),
+        Parameter('duration', kind=int, default=20,
+                  description='Number of seconds of video to play'),
+    ]
+
+    def setup(self, context):
+        super(YoutubePlayback, self).setup(context)
+
+        self.command = 'am start -a {} {}'.format(self.action, self.video_url)
+
+    def run(self, context):
+        self.target.execute(self.command)
+
+        time.sleep(self.duration)