Removed "compositor" child window that was created by the GPU process.

ui/gfx/gl/gl_context.cc

Index: ui/gfx/gl/gl_context.cc
===================================================================
--- ui/gfx/gl/gl_context.cc	(revision 83213)
+++ ui/gfx/gl/gl_context.cc	(working copy)
@@ -13,6 +13,15 @@
 
 namespace gfx {
 
+void GLContext::ReleaseCurrent() {
+  // TODO(apatrick): Implement this in GLContext derivatives.
+}
+
+GLSurface* GLContext::GetSurface() {
+  // TODO(apatrick): Remove this when surfaces are split from contexts.
+  return NULL;
+}
+
 unsigned int GLContext::GetBackingFrameBufferObject() {
   return 0;
 }