tools/gn: Convert for loops to use the new range-based loops in C++11.

tools/gn/ninja_binary_target_writer.cc

Index: tools/gn/ninja_binary_target_writer.cc
diff --git a/tools/gn/ninja_binary_target_writer.cc b/tools/gn/ninja_binary_target_writer.cc
index e6b0e91d29620033537c53af8e3dcbb824f47952..84b819bcd2394fffa00a2a1c161a65aec9cd3af0 100644
--- a/tools/gn/ninja_binary_target_writer.cc
+++ b/tools/gn/ninja_binary_target_writer.cc
@@ -441,10 +441,9 @@ void NinjaBinaryTargetWriter::WriteOrderOnlyDependencies(
     out_ << " ||";
 
     // Non-linkable targets.
-    for (size_t i = 0; i < non_linkable_deps.size(); i++) {
+    for (const auto& non_linkable_dep : non_linkable_deps) {
       out_ << " ";
-      path_output_.WriteFile(
-          out_, non_linkable_deps[i]->dependency_output_file());
+      path_output_.WriteFile(out_, non_linkable_dep->dependency_output_file());
     }
   }
 }