Moving tests and driver refactoring.

Author: David Ungar

include/swift/Driver/Compilation.h

@@ -286,7 +286,7 @@ class Compilation {
   const bool EnableSourceRangeDependencies;
 
   /// May not actually use them if e.g. there is a new input
-  bool UseSourceRangeDependencies = false;
+  bool UseSourceRangeDependencies;
 
 public:
   /// Will contain a comparator if an argument demands it.

include/swift/Driver/ExperimentalDependencyDriverGraph.h

@@ -313,7 +313,7 @@ class ModuleDepGraph {
   /// Record a new (to this graph) Job.
   void addIndependentNode(const driver::Job *);
 
-  std::vector<std::string> getExternalDependencies() const;
+  std::vector<StringRef> getExternalDependencies() const;
 
   void markExternal(SmallVectorImpl<const driver::Job *> &uses,
                     StringRef externalDependency);

lib/Driver/Compilation.cpp

@@ -133,9 +133,9 @@ void ModuleDepGraph::addIndependentNode(const Job *job) {
   jobsBySwiftDeps.insert(std::make_pair(getSwiftDeps(job), job));
 }
 
-std::vector<std::string> ModuleDepGraph::getExternalDependencies() const {
-  return std::vector<std::string>(externalDependencies.begin(),
-                                  externalDependencies.end());
+std::vector<StringRef> ModuleDepGraph::getExternalDependencies() const {
+  return std::vector<StringRef>(externalDependencies.begin(),
+                                externalDependencies.end());
 }
 
 // Add every (swiftdeps) use of the external dependency to uses.