Change glimage to accept a type.

gpu/GLES2/extensions/CHROMIUM/CHROMIUM_map_image.txt

Index: gpu/GLES2/extensions/CHROMIUM/CHROMIUM_map_image.txt
diff --git a/gpu/GLES2/extensions/CHROMIUM/CHROMIUM_map_image.txt b/gpu/GLES2/extensions/CHROMIUM/CHROMIUM_map_image.txt
index 6304fdace0feeb68efe850ed3187722a73ec4ead..d83b0fea36221c76a48a63a23f049a7c3637e901 100644
--- a/gpu/GLES2/extensions/CHROMIUM/CHROMIUM_map_image.txt
+++ b/gpu/GLES2/extensions/CHROMIUM/CHROMIUM_map_image.txt
@@ -17,7 +17,9 @@ Dependencies
 Overview
 
     This extension allows for more efficient uploading of texture data through
-    Chromium's OpenGL ES 2.0 implementation.
+    Chromium's OpenGL ES 2.0 implementation as well as enable hardware overlay
+    support by providing avility to create buffers capable of being scanned out
+    directly by the display controller.
 
     For security reasons Chromium accesses the GPU from a separate process. User
     processes are not allowed to access the GPU directly. This multi-process
@@ -39,7 +41,7 @@ New Tokens
 New Procedures and Functions
 
     GLuint CreateImageCHROMIUM (GLsizei width, GLsizei height,
-                                GLenum internalformat)
+                                GLenum internalformat, GLenum usage)
 
     Allocate an image with width equal to <width> and height equal
     to <height> stored in format <internalformat>.
@@ -49,26 +51,25 @@ New Procedures and Functions
 
     INVALID_VALUE is generated if <width> or <height> is nonpositive.
 
+    INVALID_ENUM is generated if <usage> is not one of READ_WRITE and
+    SCANOUT.
+
     void DestroyImageCHROMIUM (GLuint image_id)
 
     Frees the image previously allocated by a call to CreateImageCHROMIUM.
 
     INVALID_OPERATION is generated if <image_id> is not a valid image id.
 
-    void* MapImageCHROMIUM (GLuint image_id, GLenum access)
+    void* MapImageCHROMIUM (GLuint image_id)
 
     Returns a pointer to in the user memory for the application to modify
-    the image. <access> parameter defines if the user will read or write the
-    pixels.
+    the image. Returns null is the image was not created with READ_WRITE usage.
 
     INVALID_OPERATION is generated if <image_id> is not a valid image id.
 
     INVALID_OPERATION is generated if the image was already mapped by a previous
     call to this method.
 
-    INVALID_ENUM is generated if <access> is not one of WRITE_ONLY, READ_ONLY
-    and READ_WRITE.
-
     void UnmapImageCHROMIUM (GLuint image_id)
 
     Removes the mapping created by a call to MapImageCHROMIUM.