Add PPDProvider barebones implementation and associated cache skeleton.

chromeos/chromeos_paths.cc

Index: chromeos/chromeos_paths.cc
diff --git a/chromeos/chromeos_paths.cc b/chromeos/chromeos_paths.cc
index 58c4f20a41fff39836ad3e8531a390345b8e2e3b..0cf6abda0762157d65efec03bfb2cc516749406a 100644
--- a/chromeos/chromeos_paths.cc
+++ b/chromeos/chromeos_paths.cc
@@ -56,6 +56,9 @@ const base::FilePath::CharType kDeviceColorProfileDirectory[] =
 const base::FilePath::CharType kDeviceExtensionLocalCache[] =
     FILE_PATH_LITERAL("/var/cache/external_cache");
 
+const base::FilePath::CharType kPrinterDriversCacheDir[] =
+    FILE_PATH_LITERAL("/var/cache/print_drivers");
+
 bool PathProvider(int key, base::FilePath* result) {
   switch (key) {
     case FILE_DEFAULT_APP_ORDER:
@@ -97,6 +100,9 @@ bool PathProvider(int key, base::FilePath* result) {
     case DIR_DEVICE_EXTENSION_LOCAL_CACHE:
       *result = base::FilePath(kDeviceExtensionLocalCache);
       break;
+    case DIR_PRINTER_DRIVERS_CACHE:
+      *result = base::FilePath(kPrinterDriversCacheDir);
+      break;
     default:
       return false;
   }