update_engine: Update to build against libchrome-271506.

BUG=chromium:375032
TEST=`FEATURES=test emerge-$BOARD update_engine`

Change-Id: Ia7be302c12b439ad8aece51c9cbe128086626620
Reviewed-on: https://chromium-review.googlesource.com/201045
Tested-by: Ben Chan <benchan@chromium.org>
Reviewed-by: Alex Deymo <deymo@chromium.org>
Commit-Queue: Ben Chan <benchan@chromium.org>

hardware.cc

diff --git a/hardware.cc b/hardware.cc
index 3a11129..77e00f1 100644
--- a/hardware.cc
+++ b/hardware.cc
@@ -177,7 +177,7 @@
                                              sizeof(value_buffer));
   if (rv != NULL) {
     string return_value(value_buffer);
-    TrimWhitespaceASCII(return_value, TRIM_ALL, &return_value);
+    base::TrimWhitespaceASCII(return_value, base::TRIM_ALL, &return_value);
     return return_value;
   }