command_buffer: Make inactive bound uniforms reserve the location

gpu/GLES2/extensions/CHROMIUM/CHROMIUM_bind_uniform_location.txt

 Name
 
     CHROMIUM_bind_uniform_location
 
 Name Strings
 
     GL_CHROMIUM_bind_uniform_location
 
 Version
 
@@ skipping 86 matching lines @@
 
     When a program is linked, any active uniforms without a binding specified
     through BindUniformLocation will be automatically be bound to locations by
     the GL.  Such bindings can be queried using the command
     GetUniformLocation.
 
     BindUniformLocation may be issued before any shader objects are attached
     to a program object.  Hence it is allowed to bind any name (except a name
     starting with "gl_") to an index, including a name that is never used as a
     uniform in any shader object.  Assigned bindings for uniform variables
-    that do not exist or are not active are ignored.
+    that do not exist or are not active are ignored. Using such bindings
+    behaves as if passed location was -1.
 
     It is possible for an application to bind more than one uniform name to
     the same location.  This is referred to as aliasing.  This will only work
     if only one of the aliased uniforms is active in the executable program,
     or if no path through the shader consumes more than one uniform of a set
     of uniforms aliased to the same location.  If two statically used uniforms
     in a program are bound to the name location, link must fail.
 
 Errors
 
     None.
 
 New State
 
     None.
 
 Revision History
 
     7/20/2012    Documented the extension
     9/8/2015     Require program link to fail if two statically used uniforms
                  are bound to the same location.
+    11/6/2015    Require inactive and non-existing, bound uniform locations
+                 to behave like location -1.
 
+