PPAPI: Update pp_var.h documentation for Resource vars.

ppapi/api/pp_var.idl

Index: ppapi/api/pp_var.idl
diff --git a/ppapi/api/pp_var.idl b/ppapi/api/pp_var.idl
index 425d99ba7bfb6ff854601fb9b8a59786966ea30d..75b7e03263ed98ef0fd24072b7503be12ab81663 100644
--- a/ppapi/api/pp_var.idl
+++ b/ppapi/api/pp_var.idl
@@ -45,15 +45,15 @@ enum PP_VarType {
    * The Var represents a string. The <code>as_id</code> field is used to
    * identify the string, which may be created and retrieved from the
    * <code>PPB_Var</code> interface. These objects are reference counted, so
-   * AddRef and Release must be used properly to avoid memory leaks.
+   * AddRef() and Release() must be used properly to avoid memory leaks.
    */
   PP_VARTYPE_STRING = 5,
 
   /**
    * Represents a JavaScript object. This vartype is not currently usable
    * from modules, although it is used internally for some tasks. These objects
-   * are reference counted, so AddRef and Release must be used properly to avoid
-   * memory leaks.
+   * are reference counted, so AddRef() and Release() must be used properly to
+   * avoid memory leaks.
    */
   PP_VARTYPE_OBJECT = 6,
 
@@ -61,7 +61,7 @@ enum PP_VarType {
    * Represents an array of Vars. The <code>as_id</code> field is used to
    * identify the array, which may be created and manipulated from the
    * <code>PPB_VarArray</code> interface. These objects are reference counted,
-   * so AddRef and Release must be used properly to avoid memory leaks.
+   * so AddRef() and Release() must be used properly to avoid memory leaks.
    */
   PP_VARTYPE_ARRAY = 7,
 
@@ -69,7 +69,8 @@ enum PP_VarType {
    * Represents a mapping from strings to Vars. The <code>as_id</code> field is
    * used to identify the dictionary, which may be created and manipulated from
    * the <code>PPB_VarDictionary</code> interface. These objects are reference
-   * counted, so AddRef and Release must be used properly to avoid memory leaks.
+   * counted, so AddRef() and Release() must be used properly to avoid memory
+   * leaks.
    */
   PP_VARTYPE_DICTIONARY = 8,
 
@@ -78,15 +79,24 @@ enum PP_VarType {
    * represents Typed Arrays in JavaScript. Unlike JavaScript 'Array', it is
    * only meant to contain basic numeric types, and is always stored
    * contiguously. See PPB_VarArrayBuffer_Dev for functions special to
-   * ArrayBuffer vars. These objects are reference counted, so AddRef and
-   * Release must be used properly to avoid memory leaks.
+   * ArrayBuffer vars. These objects are reference counted, so AddRef() and
+   * Release() must be used properly to avoid memory leaks.
    */
   PP_VARTYPE_ARRAY_BUFFER = 9,
 
   /**
-   * Resources are not currently supported but will be added in the future
-   * These objects are reference counted, so AddRef and Release must be used
-   * properly to avoid memory leaks.
+   * This type allows the <code>PP_Var</code> to wrap a <code>PP_Resource
+   * </code>. This can be useful for sending or receiving some types of
+   * <code>PP_Resource</code> using <code>PPB_Messaging</code> or
+   * <code>PPP_Messaging</code>.
+   *
+   * These objects are reference counted, so AddRef() and Release() must be used
+   * properly to avoid memory leaks. Under normal circumstances, the PP_Var will

[raymes, 2014/04/09 00:16:18]

nit (here and below): not sure if we should be consistent with PP_Var vs
<code>PP_Var</code> (and the same for PP_Resource).

+   * implicitly hold a reference count on the PP_Resource on your behalf. For
+   * example, if you call VarFromResource(), it implicitly calls
+   * PPB_Core::AddRefResource() on the PP_Resource. Likewise, PPB_Var::Release()
+   * on a Resource <code>PP_Var</code> will invoke PPB_Core::ReleaseResource()
+   * when the Var reference count goes to zero.
    */
   PP_VARTYPE_RESOURCE = 10
 };