Some minor tweaks to doxygen code. Namely adding @file sections to the start 
of many files.
Review URL: http://codereview.chromium.org/6261031

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@73030 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/ppapi/c/ppb_var.h b/ppapi/c/ppb_var.h
index 8d84bf3..9d2a268 100644
--- a/ppapi/c/ppb_var.h
+++ b/ppapi/c/ppb_var.h
@@ -16,13 +16,17 @@
 #define PPB_VAR_INTERFACE "PPB_Var;0.4"
 
 /**
+ * @file
+ * Defines the API ...
+ */
+
+/**
  *
  * @addtogroup Enums
  * @{
  */
 
 /**
- * @file
  * Defines the PPB_Var struct.
  * See http://code.google.com/p/ppapi/wiki/InterfacingWithJavaScript
  * for general information on using this interface.