Reland of Revert of gpu: introduce glCopySubTextureCHROMIUM (patchset #1 id:1 of https://codereview…

ui/gl/gl_image_stub.cc

Index: ui/gl/gl_image_stub.cc
diff --git a/ui/gl/gl_image_stub.cc b/ui/gl/gl_image_stub.cc
index 1c8e469745f984a75206d220c4e691b6b925dec0..bc3fc6c1ae90cade5cb25afdc5715fe5167c4e39 100644
--- a/ui/gl/gl_image_stub.cc
+++ b/ui/gl/gl_image_stub.cc
@@ -14,7 +14,9 @@ gfx::Size GLImageStub::GetSize() { return gfx::Size(1, 1); }
 
 bool GLImageStub::BindTexImage(unsigned target) { return true; }
 
-bool GLImageStub::CopyTexImage(unsigned target) { return true; }
+bool GLImageStub::CopyTexSubImage(unsigned target, int xoffset, int yoffset) {
+  return false;
+}
 
 bool GLImageStub::ScheduleOverlayPlane(gfx::AcceleratedWidget widget,
                                        int z_order,