Support explicit pools in actions

tools/gn/builder.h

Index: tools/gn/builder.h
diff --git a/tools/gn/builder.h b/tools/gn/builder.h
index e10df4d86d07aeb5f35718b4086ea51877ad7474..e9647e901aad5d0f64420237f454f485806218fe 100644
--- a/tools/gn/builder.h
+++ b/tools/gn/builder.h
@@ -14,6 +14,7 @@
 #include "tools/gn/label_ptr.h"
 #include "tools/gn/unique_vector.h"
 
+class ActionValues;
 class Err;
 class Loader;
 class ParseNode;
@@ -117,6 +118,7 @@ class Builder {
   // if anything isn't found or if the type doesn't match.
   bool ResolveDeps(LabelTargetVector* deps, Err* err);
   bool ResolveConfigs(UniqueVector<LabelConfigPair>* configs, Err* err);
+  bool ResolveActionValues(ActionValues* action_values, Err* err);
   bool ResolveToolchain(Target* target, Err* err);
   bool ResolvePools(Toolchain* toolchain, Err* err);