Remove remaining legacy SplitString calls.

base/process/process_metrics_linux.cc

Index: base/process/process_metrics_linux.cc
diff --git a/base/process/process_metrics_linux.cc b/base/process/process_metrics_linux.cc
index b282ff0a57a38300ded3b3c8be813ad25a2d2f22..adca7c5ee23bd53914342cffd2aab166402fe920 100644
--- a/base/process/process_metrics_linux.cc
+++ b/base/process/process_metrics_linux.cc
@@ -316,8 +316,9 @@ bool ProcessMetrics::GetWorkingSetKBytesTotmaps(WorkingSetKBytes *ws_usage)
       return false;
   }
 
-  std::vector<std::string> totmaps_fields;
-  SplitStringAlongWhitespace(totmaps_data, &totmaps_fields);
+  std::vector<std::string> totmaps_fields = SplitString(
+      totmaps_data, base::kWhitespaceASCII, base::KEEP_WHITESPACE,
+      base::SPLIT_WANT_NONEMPTY);
 
   DCHECK_EQ("Pss:", totmaps_fields[kPssIndex-1]);
   DCHECK_EQ("Private_Clean:", totmaps_fields[kPrivate_CleanIndex - 1]);