Move flush id from WebGraphicsContext3DImpl to GLES2Implementation.

mojo/gpu/mojo_gles2_impl_autogen.cc

Index: mojo/gpu/mojo_gles2_impl_autogen.cc
diff --git a/mojo/gpu/mojo_gles2_impl_autogen.cc b/mojo/gpu/mojo_gles2_impl_autogen.cc
index 09a0d38278cb1d86d3fd2951347916384864b335..2e0c661eec8671d1214bf8833f8283f5ae31887f 100644
--- a/mojo/gpu/mojo_gles2_impl_autogen.cc
+++ b/mojo/gpu/mojo_gles2_impl_autogen.cc
@@ -1709,6 +1709,10 @@ void MojoGLES2Impl::FlushDriverCachesCHROMIUM() {
   MojoGLES2MakeCurrent(context_);
   glFlushDriverCachesCHROMIUM();
 }
+GLuint MojoGLES2Impl::GetLastFlushIdCHROMIUM() {
+  MojoGLES2MakeCurrent(context_);
+  return glGetLastFlushIdCHROMIUM();
+}
 void MojoGLES2Impl::MatrixLoadfCHROMIUM(GLenum matrixMode, const GLfloat* m) {
   MojoGLES2MakeCurrent(context_);
   glMatrixLoadfCHROMIUM(matrixMode, m);