Revert of gpu: Add CHROMIUM_sync_query extension.

gpu/GLES2/extensions/CHROMIUM/CHROMIUM_sync_query.txt

-Name
-
-    CHROMIUM_sync_query
-
-Name Strings
-
-    GL_CHROMIUM_sync_query
-
-Version
-
-    Last Modifed Date: April 15, 2014
-
-Dependencies
-
-    OpenGL ES 2.0 is required.
-
-    EXT_occlusion_query_boolean is required.
-
-Overview
-
-    This extension provides a query mechanism that allow for synchronization
-    between the host CPU and the GPU, which may be accessing the same
-    resources (typically memory).
-
-    This extension is useful in conjunction with CHROMIUM_map_image to
-    determine when it is safe to access a mapped image. Once the result of
-    a COMMANDS_COMPLETED_CHROMIUM query is available, all drawing commands
-    issued before the query must have finished. This ensures that the memory
-    corresponding to the issued commands can be safely modified (assuming no
-    other outstanding drawing commands are issued subsequent to the query).
-
-New Procedures and Functions
-
-    None.
-
-Errors
-
-    None.
-
-New Tokens
-
-    Accepted by the <target> parameter of BeginQueryEXT, EndQueryEXT,
-    and GetQueryivEXT:
-
-        COMMANDS_COMPLETED_CHROMIUM                     0x84F7
-
-New State
-
-    None.
-
-Revision History
-
-    4/15/2014   Documented the extension