Added method to synchronize command buffers within GpuControl.

gpu/gles2_conform_support/egl/display.cc

Index: gpu/gles2_conform_support/egl/display.cc
diff --git a/gpu/gles2_conform_support/egl/display.cc b/gpu/gles2_conform_support/egl/display.cc
index b82807916e895683893fb44c6cb7343d4f801af7..6152408876763fd1e4d80e8510f8a858da11a2c4 100644
--- a/gpu/gles2_conform_support/egl/display.cc
+++ b/gpu/gles2_conform_support/egl/display.cc
@@ -340,6 +340,10 @@ bool Display::IsGpuChannelLost() {
   return false;
 }
 
+void Display::EnsureWorkVisible() {
+  // This is only relevant for out-of-process command buffers.
+}
+
 gpu::CommandBufferNamespace Display::GetNamespaceID() const {
   return gpu::CommandBufferNamespace::IN_PROCESS;
 }