Factor out a system_properties interface for interacting with getprop/setprop.

tools/telemetry/telemetry/core/backends/adb_commands.py

Index: tools/telemetry/telemetry/core/backends/adb_commands.py
diff --git a/tools/telemetry/telemetry/core/backends/adb_commands.py b/tools/telemetry/telemetry/core/backends/adb_commands.py
index 9d067cafef786d6ed56802813966af7c56c53e1f..e4cc9952e508d7079c804fd76a4739316d8b9622 100644
--- a/tools/telemetry/telemetry/core/backends/adb_commands.py
+++ b/tools/telemetry/telemetry/core/backends/adb_commands.py
@@ -57,12 +57,16 @@ class AdbCommands(object):
   """A thin wrapper around ADB"""
 
   def __init__(self, device):
-    self._adb = android_commands.AndroidCommands(device)
+    self._adb = android_commands.AndroidCommands(device, api_strict_mode=True)
     self._device = device
 
   def device(self):
     return self._device
 
+  @property
+  def system_properties(self):
+    return self._adb.system_properties
+
   def Adb(self):
     return self._adb
 
@@ -193,8 +197,8 @@ def SetupPrebuiltTools(adb):
   # Prebuilt tools from r226197.
   has_prebuilt = sys.platform.startswith('linux')
   if has_prebuilt:
-    abi = adb.RunShellCommand('getprop ro.product.cpu.abi')
-    has_prebuilt = abi and abi[0].startswith('armeabi')
+    abi = adb.system_properties['ro.product.cpu.abi']
+    has_prebuilt = abi.startswith('armeabi')
   if not has_prebuilt:
     logging.error(
         'Prebuilt android tools only available for Linux host and ARM device.')