Fix stack-use-after-scope issues in WeaveWiFiSetupTest test cases.

This CL fixes a stack-use-after-scope issue, detected by ASAN, in the
WeaveWiFiSetupTest.OfflineLongTimeWithNoSsid and
WeaveWiFiSetupTest.OfflineLongTimeWithSsid test cases, where the
'time_stamp' variable on the stack is captured by reference for used in
lambdas. The 'time_stamp' variable should thus be defined in a scope
that survives until after lambdas are executed.

BUG=chromium:717228
TEST=`USE='clang asan' emerge-$BOARD libweave`

Change-Id: Ib1013a5f020d6f233d45537fdf6f32ce2f3d8e56
Reviewed-on: https://weave-review.googlesource.com/9970
Reviewed-by: Eric Caruso <ejcaruso@google.com>

src/weave_unittest.cc

diff --git a/src/weave_unittest.cc b/src/weave_unittest.cc
index fba9a8a..d7855df 100644
--- a/src/weave_unittest.cc
+++ b/src/weave_unittest.cc
@@ -474,9 +474,9 @@
   NotifyNetworkChanged(provider::Network::State::kOnline,
                        base::TimeDelta::FromHours(15));
 
+  auto time_stamp = task_runner_.GetClock()->Now();
   {
     InSequence s;
-    auto time_stamp = task_runner_.GetClock()->Now();
 
     EXPECT_CALL(wifi_, StartAccessPoint(MatchesRegex("TEST_NAME.*prv")))
         .WillOnce(InvokeWithoutArgs([this, &time_stamp]() {
@@ -505,9 +505,9 @@
   NotifyNetworkChanged(provider::Network::State::kOnline,
                        base::TimeDelta::FromHours(15));
 
+  auto time_stamp = task_runner_.GetClock()->Now();
   {
     InSequence s;
-    auto time_stamp = task_runner_.GetClock()->Now();
     for (size_t i = 0; i < 10; ++i) {
       EXPECT_CALL(wifi_, StartAccessPoint(MatchesRegex("TEST_NAME.*prv")))
           .WillOnce(InvokeWithoutArgs([this, &time_stamp]() {