Fix some clang warnings with -Wmissing-braces in base.

base/third_party/nspr/prtime.cc

Index: base/third_party/nspr/prtime.cc
diff --git a/base/third_party/nspr/prtime.cc b/base/third_party/nspr/prtime.cc
index 9335b01de863ca5fdef0e0c3122396a5fd5ed3bb..a7c5a3a949680ae87541d86e8c032a9fb432eab5 100644
--- a/base/third_party/nspr/prtime.cc
+++ b/base/third_party/nspr/prtime.cc
@@ -107,9 +107,9 @@ PR_ImplodeTime(const PRExplodedTime *exploded)
     static const PRTime kSecondsToMicroseconds = static_cast<PRTime>(1000000);
 #if defined(OS_WIN)
    // Create the system struct representing our exploded time.
-    SYSTEMTIME st = {0};
-    FILETIME ft = {0};
-    ULARGE_INTEGER uli = {0};
+    SYSTEMTIME st = {};
+    FILETIME ft = {};
+    ULARGE_INTEGER uli = {};
 
     st.wYear = exploded->tm_year;
     st.wMonth = static_cast<WORD>(exploded->tm_month + 1);