Proposing new CHROMIUM_sync_point API.

gpu/GLES2/extensions/CHROMIUM/CHROMIUM_sync_point.txt

 Name
 
     CHROMIUM_sync_point
 
 Name Strings
 
     GL_CHROMIUM_sync_point
 
 Version
 
-    Last Modifed Date: February 25, 2013
+    Last Modifed Date: September 8, 2015
 
 Dependencies
 
     OpenGL ES 2.0 is required.
 
 Overview
 
     This extension allows a client to order operations between contexts.
 
+    This extension introduces the concept of "fence syncs" and "sync token".
+    Inserted fence syncs represents a position in the command stream of a
+    context. Sync tokens are generated from fence syncs and allows another
+    context to issue a "wait" command on the sync token. This wait command
+    will then guarantee that commands before the inserted fence sync are
+    submitted before commands after the sync token wait.
+
     This extension implements a small subset of ARB_sync, with weaker
     guarantees. In particular it doesn't ensure commands are actually executed
     by the server, it only guarantees submission order.
 
     It does however guarantee operation order with respect to
     ConsumeTextureCHROMIUM and ProduceTextureCHROMIUM from
     CHROMIUM_texture_mailbox, if present.
 
 Issues
 
     None
 
-New Tokens
-
-    None
-
 New Procedures and Functions
 
     The command
 
-        uint InsertSyncPointCHROMIUM()
+        uint InsertFenceSyncCHROMIUM()
 
-    flushes the stream of commands for the current context and creates and
-    inserts a sync point. The sync point acts as a fence, which is signaled when
-    previous commands have been submitted to the server, or when the context is
-    destroyed, whichever happens first. The sync point name is returned. The
-    sync point is implicitly deleted when it becomes signaled. The sync point
-    namespace is shared between all contexts on the same server, including other
-    context groups.
-
+    inserts a fence sync in the current command stream. The fence sync is
+    signaled when previous commands have been submitted to the server, or when
+    the context is destroyed, whichever happens first. The fence sync name is
+    only visible for the current context. The returned fence sync name cannot
+    be waited upon directly, but once the command is flushed to the server it
+    can be converted to a sync token using GenSyncTokenCHROMIUM which is
+    waitable.
 
     The command
 
-        void WaitSyncPointCHROMIUM(uint sync_point)
+        void GenSyncTokenCHROMIUM(uint fence_sync, GLbyte *sync_token)
+
+    converts <fence_sync> which is only visible to the current context to a
+    sync token which may be waited upon by any contexts on the same server.
+    The <fence_sync> command must be flushed before this function may be
+    called, otherwise an INVALID_OPERATION error is generated. The generated
+    <sync_token> must be generated on the same context as when
+    InsertSyncPointCHROMIUM was called. The <sync_token> can be passed and
+    used by any context on the same server, including other context groups.
+
+    <sync_token> returns a GL_SYNC_POINT_SIZE_CHROMIUM byte sized name.
+
+    The command
+
+        void WaitSyncTokenCHROMIUM(GLbyte *sync_token)
 
     causes the current context to stop submitting commands until the specified
-    sync point becomes signaled. This is implemented as a server-side wait.
-    <sync_point> is the name of the sync point to wait for. If <sync_point>
-    isn't a valid sync point returned by InsertSyncPointCHROMIUM, or if the sync
-    point has already been deleted, the command is equivalent to a no-op and no
-    error is generated.
+    fence sync becomes signaled. This is implemented as a server-side wait.
+    <sync_token> is a sync token generated by GenSyncPointCHROMIUM. If
+    <sync_token> isn't a valid sync token returned by GenSyncPointCHROMIUM, the
+    command is equivalent to a no-op and no error is generated.
+
+New Tokens
+
+    The size of a sync token name in bytes.
+
+        GL_SYNC_TOKEN_SIZE_CHROMIUM                        12
 
 Errors
 
-    None.
+    INVALID_VALUE is generated if the <fence_sync> parameter of
+    GenSyncPointCHROMIUM is not a valid local fence sync name.
+
+    INVALID_OPERATION is generated if the <fence_sync> parameter of
+    GenSyncPointCHROMIUM has not been flushed to the server.
 
 New State
 
     None.
 
 Revision History
 
     2/25/2013    Documented the extension
+
+    9/8/2015     Modified functions to InsertFenceSyncCHROMIUM,
+    GenSyncTokenCHROMIUM, and WaitSyncTokenCHROMIUM.