Set file tokens for NaCl main nexe if available to enable validation caching.

components/nacl/browser/nacl_browser.h

Index: components/nacl/browser/nacl_browser.h
diff --git a/components/nacl/browser/nacl_browser.h b/components/nacl/browser/nacl_browser.h
index 51d19e4efdd89512bdbaa17ee85579c58c01ef57..93dcb4230cf12b94ee098ba4052beb05e75f2668 100644
--- a/components/nacl/browser/nacl_browser.h
+++ b/components/nacl/browser/nacl_browser.h
@@ -74,6 +74,12 @@ class NaClBrowser {
 
   int GetProcessGdbDebugStubPort(int process_id);
 
+  enum ValidationCacheStatus {
+    CACHE_MISS = 0,
+    CACHE_HIT,
+    CACHE_MAX
+  };
+
   bool ValidationCacheIsEnabled() const {
     return validation_cache_is_enabled_;
   }