[Android] Break GTest emulator launching into a separate function.

build/android/emulator.py

Index: build/android/emulator.py
diff --git a/build/android/emulator.py b/build/android/emulator.py
index 77c9a75daa11963c0de2502d33bc828363f5fef1..543a98e172e00b5081e262c65a88495a477a361b 100755
--- a/build/android/emulator.py
+++ b/build/android/emulator.py
@@ -21,6 +21,7 @@ import time
 
 from pylib import android_commands
 from pylib import cmd_helper
+from pylib.utils import time_profile
 
 # adb_interface.py is under ../../third_party/android_testrunner/
 sys.path.append(os.path.join(os.path.abspath(os.path.dirname(__file__)), '..',
@@ -99,6 +100,33 @@ def _GetAvailablePort():
       return port
 
 
+def LaunchEmulators(emulator_count, fast_and_loose=False):
+  """Launch multiple emulators and wait for them to boot.
+
+  Args:
+    emulator_count: number of emulators to launch.
+
+  Returns:
+    List of emulators.
+  """
+  emulators = []
+  for n in xrange(emulator_count):
+    t = time_profile.TimeProfile('Emulator launch %d' % n)
+    avd_name = None
+    if n > 0:
+      # Creates a temporary AVD for the extra emulators.
+      avd_name = 'run_tests_avd_%d' % n
+    logging.info('Emulator launch %d with avd_name=%s', n, avd_name)
+    emulator = Emulator(avd_name, fast_and_loose)
+    emulator.Launch(kill_all_emulators=n == 0)
+    t.Stop()
+    emulators.append(emulator)
+  # Wait for all emulators to boot completed.
+  for emulator in emulators:
+    emulator.ConfirmLaunch(True)
+  return emulators
+
+
 class Emulator(object):
   """Provides the methods to lanuch/shutdown the emulator.