gpu: Add a new extension CHROMIUM_deschedule.

gpu/GLES2/extensions/CHROMIUM/CHROMIUM_deschedule.txt

Index: gpu/GLES2/extensions/CHROMIUM/CHROMIUM_deschedule.txt
diff --git a/gpu/GLES2/extensions/CHROMIUM/CHROMIUM_deschedule.txt b/gpu/GLES2/extensions/CHROMIUM/CHROMIUM_deschedule.txt
new file mode 100644
index 0000000000000000000000000000000000000000..ed04d5b26e6c59334acd9b22e7d8ae9b019508d5
--- /dev/null
+++ b/gpu/GLES2/extensions/CHROMIUM/CHROMIUM_deschedule.txt
@@ -0,0 +1,48 @@
+Name
+
+    CHROMIUM_deschedule
+
+Name Strings
+
+    GL_CHROMIUM_deschedule
+
+Version
+
+    Last Modifed Date: May 27, 2016
+
+Dependencies
+
+    OpenGL ES 2.0 is required.
+
+Overview
+
+    This extension provides a mechanism for clients to throttle the submission
+    of commands on the service side.
+
+Issues
+
+    None
+
+New Tokens
+
+    None
+
+New Procedures and Functions
+
+    void DescheduleUntilFinishedCHROMIUM()
+
+    This command prevents decoding of subsequent commands until all previously
+    issued commands have finished. Its behavior is equivalent to a service side
+    glFinish.
+
+Errors
+
+    None.
+
+New State
+
+    None.
+
+Revision History
+
+    5/27/2016    Documented the extension