gpu: Add CHROMIUM_copy_image extension.

ui/gl/gl_image_egl.cc

Index: ui/gl/gl_image_egl.cc
diff --git a/ui/gl/gl_image_egl.cc b/ui/gl/gl_image_egl.cc
index fe452c73eb3b9a4e86aec47f47171f5e54dda81c..1e74aaceeb687cdd18695e4f023540d6a487f1b3 100644
--- a/ui/gl/gl_image_egl.cc
+++ b/ui/gl/gl_image_egl.cc
@@ -78,6 +78,14 @@ bool GLImageEGL::CopyTexSubImage(unsigned target,
   return false;
 }
 
+bool GLImageEGL::CopySubImageData(unsigned texture_id,
+                                  const gfx::Point& offset,
+                                  const gfx::Rect& rect,
+                                  GLFence* in_fence,
+                                  GLFence* out_fence) {
+  return false;
+}
+
 bool GLImageEGL::ScheduleOverlayPlane(gfx::AcceleratedWidget widget,
                                       int z_order,
                                       gfx::OverlayTransform transform,