glBindTexImage2DCHROMIUM should retain pixel format.

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 a4abd2489c3d3d380e0131796a35d394a9123716..9b352f432d553f965510e8694d1e6979cec2a62f 100644
--- a/ui/gl/gl_image_egl.h
+++ b/ui/gl/gl_image_egl.h
@@ -20,6 +20,7 @@ class GL_EXPORT GLImageEGL : public GLImage {
   // Overridden from GLImage:
   void Destroy(bool have_context) override;
   gfx::Size GetSize() override;
+  unsigned GetFormat() override;
   bool BindTexImage(unsigned target) override;
   void ReleaseTexImage(unsigned target) override {}
   bool CopyTexImage(unsigned target) override;