gpu: Add CHROMIUM_copy_image extension.

ui/gl/gl_image_egl.h

Index: ui/gl/gl_image_egl.h
diff --git a/ui/gl/gl_image_egl.h b/ui/gl/gl_image_egl.h
index b422092dcd679a746ab12b829ff785db25891fad..6c659b68b3f42b8368fa7251faf56b060133b5d0 100644
--- a/ui/gl/gl_image_egl.h
+++ b/ui/gl/gl_image_egl.h
@@ -29,6 +29,11 @@ class GL_EXPORT GLImageEGL : public GLImage {
   bool CopyTexSubImage(unsigned target,
                        const gfx::Point& offset,
                        const gfx::Rect& rect) override;
+  bool CopySubImageData(unsigned texture_id,
+                        const gfx::Point& offset,
+                        const gfx::Rect& rect,
+                        GLFence* in_fence,
+                        GLFence* out_fence) override;
   bool ScheduleOverlayPlane(gfx::AcceleratedWidget widget,
                             int z_order,
                             gfx::OverlayTransform transform,