platform2: Switch over to libchrome r323904

Using revision 323904 of libchrome by default. Fixed a few minor
compiler error due to a change in the new libchrome's headers.

BUG=chromium:472654
TEST=./build_packages
CQ-DEPEND=CL:264350

Change-Id: I0d57f34403f60c3d60d9159b60b498bf7ff166f3
Reviewed-on: https://chromium-review.googlesource.com/264311
Tested-by: Alex Vakulenko <avakulenko@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Trybot-Ready: Alex Vakulenko <avakulenko@chromium.org>
Commit-Queue: Alex Vakulenko <avakulenko@chromium.org>
diff --git a/metrics/libmetrics-323904.gyp b/metrics/libmetrics-323904.gyp
new file mode 100644
index 0000000..fc5bd35
--- /dev/null
+++ b/metrics/libmetrics-323904.gyp
@@ -0,0 +1,8 @@
+{
+  'variables': {
+    'libbase_ver': 323904,
+  },
+  'includes': [
+    'libmetrics.gypi',
+  ],
+}