Revert 131177 - aura: Change shared context to be offscreen for arm

gpu/command_buffer/service/gles2_cmd_decoder.h

Index: gpu/command_buffer/service/gles2_cmd_decoder.h
===================================================================
--- gpu/command_buffer/service/gles2_cmd_decoder.h	(revision 131558)
+++ gpu/command_buffer/service/gles2_cmd_decoder.h	(working copy)
@@ -87,9 +87,6 @@
   // Parameters:
   //  surface: the GL surface to render to.
   //  context: the GL context to render to.
-  //  offscreen: whether to make the context offscreen or not. When FBO 0 is
-  //      bound, offscreen contexts render to an internal buffer, onscreen ones
-  //      to the surface.
   //  size: the size if the GL context is offscreen.
   //  allowed_extensions: A string in the same format as
   //      glGetString(GL_EXTENSIONS) that lists the extensions this context
@@ -98,7 +95,6 @@
   //   true if successful.
   virtual bool Initialize(const scoped_refptr<gfx::GLSurface>& surface,
                           const scoped_refptr<gfx::GLContext>& context,
-                          bool offscreen,
                           const gfx::Size& size,
                           const DisallowedFeatures& disallowed_features,
                           const char* allowed_extensions,