Always apply UniformMatrix4fvStreamTextureMatrixCHROMIUM matrix argument.

gpu/GLES2/extensions/CHROMIUM/CHROMIUM_stream_texture_matrix.txt

 Name
 
     CHROMIUM_stream_texture_matrix
 
 Name Strings
 
     CHROMIUM_stream_texture_matrix
 
 Version
 
@@ skipping 12 matching lines @@
     of a stream texture.  Intended for use with Android SurfaceTexture, which
     doesn't provide the value until the front buffer is latched.
 
 New Procedures and Functions
 
     The command
 
        void UniformMatrix4fvStreamTextureMatrixCHROMIUM(
                GLintUniformLocation location,
                GLbooleanFalseOnly transpose,
-               const GLfloat* default_value)
+               const GLfloat* transform)
 
-    Updates a uniform to match the current stream texture's texture matrix.
-    The stream texture must be bound to the GL_TEXTURE_EXTERNAL_OES target on
-    the active texture unit.
+    Updates a uniform to match the current stream texture's texture matrix
+    multiplied by transform. The stream texture must be bound to the
+    GL_TEXTURE_EXTERNAL_OES target on the active texture unit.
 
-    If the bound texture is not a stream texture, then the default value is
+    If the bound texture is not a stream texture, then the identity matrix is
     used instead.
 
     <location> Specifies the 4x4f uniform location to be modified.
     <transpose> Specifies whether the matrix should be transposed.
-    <default_value> Provides the default matrix.
-
-    The default value is a transitionary step.  It will be removed.
+    <transform> Provides an additional transform matrix that is applied
+      prior to the the stream texture transformation matrix.
 
 Errors
 
     None.
 
 New State
 
     None.
 
 Revision History
 
     02/16/2016    Documented the extension
+    03/21/2016    Amended the interpretation of the matrix argument.