Tidy up some uses of LOG(WARNING).

Change-Id: I15b94ab5b542554ce3971684fc3d67c3b18f69fb
Reviewed-on: https://code-review.googlesource.com/7404
Reviewed-by: Paul Wankadia <junyer@google.com>
diff --git a/re2/prefilter_tree.cc b/re2/prefilter_tree.cc
index 556561f..d2f8221 100644
--- a/re2/prefilter_tree.cc
+++ b/re2/prefilter_tree.cc
@@ -294,7 +294,7 @@
     std::vector<int>* regexps) const {
   regexps->clear();
   if (!compiled_) {
-    LOG(WARNING) << "Compile() not called";
+    LOG(DFATAL) << "RegexpsGivenStrings before Compile.";
     for (size_t i = 0; i < prefilter_vec_.size(); ++i)
       regexps->push_back(static_cast<int>(i));
   } else {
diff --git a/re2/testing/filtered_re2_test.cc b/re2/testing/filtered_re2_test.cc
index 353b85d..988e71b 100644
--- a/re2/testing/filtered_re2_test.cc
+++ b/re2/testing/filtered_re2_test.cc
@@ -161,13 +161,13 @@
       pass = pass && expected[i] == v->atoms[i];
 
   if (!pass) {
-    LOG(WARNING) << "Failed " << testname;
-    LOG(WARNING) << "Expected #atoms = " << expected.size();
+    LOG(ERROR) << "Failed " << testname;
+    LOG(ERROR) << "Expected #atoms = " << expected.size();
     for (size_t i = 0; i < expected.size(); i++)
-      LOG(WARNING) << expected[i];
-    LOG(WARNING) << "Found #atoms = " << v->atoms.size();
+      LOG(ERROR) << expected[i];
+    LOG(ERROR) << "Found #atoms = " << v->atoms.size();
     for (size_t i = 0; i < v->atoms.size(); i++)
-      LOG(WARNING) << v->atoms[i];
+      LOG(ERROR) << v->atoms[i];
   }
 
   return pass;