Revert of [Android] Add a configurable environment for devil/. (RELAND 2)

build/android/pylib/constants/__init__.py

Index: build/android/pylib/constants/__init__.py
diff --git a/build/android/pylib/constants/__init__.py b/build/android/pylib/constants/__init__.py
index 1a48723d584e308175ccf2a05cf504246d9b89b7..772af93c50ef77c3729e264e2e803ce7755f5d38 100644
--- a/build/android/pylib/constants/__init__.py
+++ b/build/android/pylib/constants/__init__.py
@@ -16,7 +16,6 @@
 import devil.android.sdk.keyevent
 from devil.android.sdk import version_codes
 from devil.constants import exit_codes
-
 
 keyevent = devil.android.sdk.keyevent
 
@@ -244,12 +243,42 @@
       GetBuildType() if build_type is None else build_type))
 
 
-# TODO(jbudorick): Convert existing callers to AdbWrapper.GetAdbPath() and
-# remove this.
+def _Memoize(func):
+  def Wrapper():
+    try:
+      return func._result
+    except AttributeError:
+      func._result = func()
+      return func._result
+  return Wrapper
+
+
+def SetAdbPath(adb_path):
+  os.environ['ADB_PATH'] = adb_path
+
+
 def GetAdbPath():
-  from devil.android.sdk import adb_wrapper
-  return adb_wrapper.AdbWrapper.GetAdbPath()
-
+  # Check if a custom adb path as been set. If not, try to find adb
+  # on the system.
+  if os.environ.get('ADB_PATH'):
+    return os.environ.get('ADB_PATH')
+  else:
+    return _FindAdbPath()
+
+
+@_Memoize
+def _FindAdbPath():
+  if os.environ.get('ANDROID_SDK_ROOT'):
+    return 'adb'
+  # If envsetup.sh hasn't been sourced and there's no adb in the path,
+  # set it here.
+  try:
+    with file(os.devnull, 'w') as devnull:
+      subprocess.call(['adb', 'version'], stdout=devnull, stderr=devnull)
+    return 'adb'
+  except OSError:
+    logging.debug('No adb found in $PATH, fallback to checked in binary.')
+    return os.path.join(ANDROID_SDK_ROOT, 'platform-tools', 'adb')
 
 # Exit codes
 ERROR_EXIT_CODE = exit_codes.ERROR