Moving DependencyScanningAction to its own header and source files.

Author: qiongsiwu

clang/lib/Tooling/DependencyScanning/CMakeLists.txt

@@ -10,6 +10,7 @@ add_clang_library(clangDependencyScanning
   DependencyScanningService.cpp
   DependencyScanningWorker.cpp
   DependencyScanningTool.cpp
+  DependencyScanner.cpp
   InProcessModuleCache.cpp
   ModuleDepCollector.cpp