Write adb public key to devices during provision.

build/android/provision_devices.py

Index: build/android/provision_devices.py
diff --git a/build/android/provision_devices.py b/build/android/provision_devices.py
index 824e64202e78787d1096eedd73ddaa4e7b704dc1..e13f6f868bd89c842b31424046a8d6d2f7df7894 100755
--- a/build/android/provision_devices.py
+++ b/build/android/provision_devices.py
@@ -127,6 +127,9 @@ def WipeDeviceData(device):
     device: the device to wipe
   """
   device_authorized = device.FileExists(constants.ADB_KEYS_FILE)
+  adb_public_key = ''
+  with open(constants.ADB_PUBLIC_KEY, 'r') as f:
+    adb_public_key = f.readlines()
   if device_authorized:
     adb_keys = device.ReadFile(constants.ADB_KEYS_FILE, as_root=True)
   device.RunShellCommand('wipe data', as_root=True)
@@ -135,10 +138,13 @@ def WipeDeviceData(device):
     dir_path = '/'.join(path_list[:len(path_list)-1])
     device.RunShellCommand('mkdir -p %s' % dir_path, as_root=True)
     device.RunShellCommand('restorecon %s' % dir_path, as_root=True)
+    if 'chrome-infrastructure-adb-key' not in adb_keys:
+      adb_keys += ''.join(adb_public_key)
     device.WriteFile(constants.ADB_KEYS_FILE, adb_keys, as_root=True)
     device.RunShellCommand('restorecon %s' % constants.ADB_KEYS_FILE,
                            as_root=True)
-
+  else:
+    device.WriteFile(constants.ADB_KEYS_FILE, adb_public_key, as_root=True)
 
 def WipeDeviceIfPossible(device, timeout):
   try: