Proposing new CHROMIUM_sync_point API.

gpu/GLES2/extensions/CHROMIUM/CHROMIUM_sync_point.txt

Index: gpu/GLES2/extensions/CHROMIUM/CHROMIUM_sync_point.txt
diff --git a/gpu/GLES2/extensions/CHROMIUM/CHROMIUM_sync_point.txt b/gpu/GLES2/extensions/CHROMIUM/CHROMIUM_sync_point.txt
index 965cb44b0c066306163f84404232be632a42f644..9f1863cc0052467d5ac845a07ef50048bbfad68e 100644
--- a/gpu/GLES2/extensions/CHROMIUM/CHROMIUM_sync_point.txt
+++ b/gpu/GLES2/extensions/CHROMIUM/CHROMIUM_sync_point.txt
@@ -8,7 +8,7 @@ Name Strings
 
 Version
 
-    Last Modifed Date: February 25, 2013
+    Last Modifed Date: September 8, 2015
 
 Dependencies
 
@@ -18,6 +18,13 @@ 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.
@@ -30,39 +37,57 @@ Issues
 
     None
 
-New Tokens
+New Procedures and Functions
 
-    None
+    The command
 
-New Procedures and Functions
+        uint InsertFenceSyncCHROMIUM()
+
+    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
 
-        uint InsertSyncPointCHROMIUM()
+        void GenSyncTokenCHROMIUM(uint fence_sync, GLbyte *sync_token)
 
-    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.
+    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 WaitSyncPointCHROMIUM(uint sync_point)
+        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
 
@@ -71,3 +96,6 @@ New State
 Revision History
 
     2/25/2013    Documented the extension
+
+    9/8/2015     Modified functions to InsertFenceSyncCHROMIUM,
+    GenSyncTokenCHROMIUM, and WaitSyncTokenCHROMIUM.