Reland of Migrate DeviceUtils.ReadFile to adb_wrapper

build/android/tombstones.py

Index: build/android/tombstones.py
diff --git a/build/android/tombstones.py b/build/android/tombstones.py
index fd060ad5175f4ede192ade78ab4b15696051ccbb..94f76f1f74d130e3d85024b0f3d42027b64fdb45 100755
--- a/build/android/tombstones.py
+++ b/build/android/tombstones.py
@@ -63,7 +63,8 @@ def _GetTombstoneData(device, tombstone_file):
   Returns:
     A list of lines
   """
-  return device.ReadFile('/data/tombstones/' + tombstone_file, as_root=True)
+  return device.ReadFile(
+      '/data/tombstones/' + tombstone_file, as_root=True).splitlines()
 
 
 def _EraseTombstone(device, tombstone_file):