Basic android app implementation

tools/telemetry/telemetry/core/backends/android_app_backend.py

 # Copyright 2012 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 time
+
 from telemetry.core.backends import app_backend
+from telemetry.core.platform import android_platform_backend as \
+  android_platform_backend_module
 
 
 class AndroidAppBackend(app_backend.AppBackend):
-  def __init__(self):
-    super(AndroidAppBackend, self).__init__()
+  def __init__(self, android_platform_backend, start_intent):
+    super(AndroidAppBackend, self).__init__(app_type=start_intent.package)
+    assert isinstance(android_platform_backend,
+                      android_platform_backend_module.AndroidPlatformBackend)
+    self._android_platform_backend = android_platform_backend
+    self._start_intent = start_intent
+    self._is_running = False
 
   @property
   def pid(self):
     raise NotImplementedError
 
+  @property
+  def _adb(self):
+    return self._android_platform_backend.adb
+
   def Start(self):
-    raise NotImplementedError
+    """Start an Android app and wait for it to finish launching.
+
+    AppStory derivations can customize the wait-for-ready-state to wait
+    for a more specific event if needed.
+    """
+    # TODO(slamm): check if can use "blocking=True" instead of needing to sleep.
+    # If "blocking=True" does not work, switch sleep to "ps" check.
+    self._adb.device().StartActivity(self._start_intent, blocking=False)
+    time.sleep(9)
+    self._is_running = True
 
   def Close(self):
-    raise NotImplementedError
+    self._is_running = False
+    self._android_platform_backend.KillApplication(self._start_intent.package)
 
   def IsAppRunning(self):
-    raise NotImplementedError
+    return self._is_running
 
   def GetStandardOutput(self):
     raise NotImplementedError
 
   def GetStackTrace(self):
     raise NotImplementedError