Remove setErrorMessageCallback from WebGraphicsContext3D.

gpu/blink/webgraphicscontext3d_impl.cc

Index: gpu/blink/webgraphicscontext3d_impl.cc
diff --git a/gpu/blink/webgraphicscontext3d_impl.cc b/gpu/blink/webgraphicscontext3d_impl.cc
index 256d19a7d23b873955ce5d933d933e5d3f9035e1..8fd265beb41ba7c28a3071a64f80f1c5d5400010 100644
--- a/gpu/blink/webgraphicscontext3d_impl.cc
+++ b/gpu/blink/webgraphicscontext3d_impl.cc
@@ -30,18 +30,12 @@ WebGraphicsContext3DImpl::WebGraphicsContext3DImpl()
     : initialized_(false),
       initialize_failed_(false),
       context_lost_callback_(0),
-      error_message_callback_(0),
       gl_(NULL) {}
 
 WebGraphicsContext3DImpl::~WebGraphicsContext3DImpl() {
 
 }
 
-void WebGraphicsContext3DImpl::setErrorMessageCallback(
-    WebGraphicsContext3D::WebGraphicsErrorMessageCallback* cb) {
-  error_message_callback_ = cb;
-}
-
 void WebGraphicsContext3DImpl::setContextLostCallback(
     WebGraphicsContext3D::WebGraphicsContextLostCallback* cb) {
   context_lost_callback_ = cb;