Fix some possible performance issues found by clang-tidy

No obvious time differences when building AOSP, but these all seem like
reasonable changes.

1 files changed, 1 insertions, 1 deletions

diff --git a/dep.cc b/dep.cc
index 502ec47..4bdf9ab 100644
--- a/dep.cc
+++ b/dep.cc
@@ -534,7 +534,7 @@ class DepBuilder {
     if (found == suffix_rules_.end())
       return rule_merger;
 
-    for (shared_ptr<Rule> irule : found->second) {
+    for (const shared_ptr<Rule> &irule : found->second) {
       CHECK(irule->inputs.size() == 1);
       Symbol input = ReplaceSuffix(output, irule->inputs[0]);
       if (!Exists(input))