[base] Define CHECK comparison for signed vs. unsigned

src/log-utils.h

Index: src/log-utils.h
diff --git a/src/log-utils.h b/src/log-utils.h
index b165b3ee9a7a3951412aac5f704fe8a9b0451340..bc414e848d0bef306d37dda339974333adebad09 100644
--- a/src/log-utils.h
+++ b/src/log-utils.h
@@ -110,9 +110,9 @@ class Log {
 
   // Implementation of writing to a log file.
   int WriteToFile(const char* msg, int length) {
-    DCHECK(output_handle_ != NULL);
+    DCHECK_NOT_NULL(output_handle_);
     size_t rv = fwrite(msg, 1, length, output_handle_);
-    DCHECK(static_cast<size_t>(length) == rv);
+    DCHECK_EQ(length, rv);
     USE(rv);
     fflush(output_handle_);
     return length;