Roll src/third_party/cros_system_api/ c26789948..7e90794df (4 commits)

https://chromium.googlesource.com/chromiumos/platform2/system_api.git/+log/c267899484ba..7e90794dfac8

$ git log c26789948..7e90794df --date=short --no-merges --format='%ad %ae %s'
2019-06-24 alanlxl power_manager: Remove kScreenDimImminentSignal and kDeferScreenDimMethod
2019-07-15 zuan cryptohome: Add calls for obtaining RSUDeviceID to UserDataAuth and proxy
2019-08-02 victorhsieh system_api: rename BOOTLOCKBOX_ERROR_CANNOT_READ
2019-07-11 sjzhong system_api: Add AddDataRestoreKey and MassRemoveKeys in dbus-constants.h.

Created with:
  roll-dep src/third_party/cros_system_api

Bug: 977321
Change-Id: Id32afe66517a243302b90f7b1b182709e22b7562
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1750930Reviewed-by: Ryo Hashimoto <hashimoto@chromium.org>
Reviewed-by: Mattias Nissler <mnissler@chromium.org>
Commit-Queue: Shaojiang Zhong <sjzhong@google.com>
Cr-Commit-Position: refs/heads/master@{#686447}

DEPS

@@ -829,7 +829,7 @@ deps = {
 
   # For Linux and Chromium OS.
   'src/third_party/cros_system_api': {
-      'url': Var('chromium_git') + '/chromiumos/platform2/system_api.git' + '@' + 'c267899484bac0f024a10b32452d4cee6ffa6068',
+      'url': Var('chromium_git') + '/chromiumos/platform2/system_api.git' + '@' + '7e90794dfac8e32ce3ecc14029046d7e05fd91b2',
       'condition': 'checkout_linux',
   },