Roll cros_system_api b78cb488..19115ef1

https://chromium.googlesource.com/chromiumos/platform/system_api.git/+log/b78cb488..19115ef1

$ git log b78cb488..19115ef1 --date=short --no-merges --format='%ad %ae %s'
2017-04-10 xiyuan@google.com system-api: Add cryptohome NeedsDircryptoMigration name
2017-03-27 ejcaruso@chromium.org system_api: remove unused debugd D-Bus method name

BUG=706307
TEST=Manual.

Change-Id: I51afd2afc614a0bc5d754a48b3f1e6c6352fccf1
Reviewed-on: https://chromium-review.googlesource.com/476094
Reviewed-by: Achuith Bhandarkar <achuith@chromium.org>
Commit-Queue: Xiyuan Xia <xiyuan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#464241}

DEPS

@@ -409,7 +409,7 @@ deps_os = {
 
     # For Linux and Chromium OS.
     'src/third_party/cros_system_api':
-      Var('chromium_git') + '/chromiumos/platform/system_api.git' + '@' + 'b78cb4884c80ae158efa81b1c65c489cfbc97959',
+      Var('chromium_git') + '/chromiumos/platform/system_api.git' + '@' + '19115ef1bc72e0068951d236cdc0c549346adfda',
 
     'src/third_party/freetype/src':
       Var('chromium_git') + '/chromium/src/third_party/freetype2.git' + '@' + Var('freetype_revision'),