Add support for EXT_image_flush_external extension

ui/gl/gl_image_ozone_native_pixmap.cc

Index: ui/gl/gl_image_ozone_native_pixmap.cc
diff --git a/ui/gl/gl_image_ozone_native_pixmap.cc b/ui/gl/gl_image_ozone_native_pixmap.cc
index 0475abf9c6af5bd6278824a1dc5cb18848b238f2..8c61710f1c26e116c730ce6826c80aef68aabab2 100644
--- a/ui/gl/gl_image_ozone_native_pixmap.cc
+++ b/ui/gl/gl_image_ozone_native_pixmap.cc
@@ -101,7 +101,10 @@ EGLint FourCC(gfx::BufferFormat format) {
 
 GLImageOzoneNativePixmap::GLImageOzoneNativePixmap(const gfx::Size& size,
                                                    unsigned internalformat)
-    : GLImageEGL(size), internalformat_(internalformat) {}
+    : GLImageEGL(size),
+      internalformat_(internalformat),
+      has_image_flush_external_(
+          GLSurfaceEGL::HasEGLExtension("EGL_EXT_image_flush_external")) {}
 
 GLImageOzoneNativePixmap::~GLImageOzoneNativePixmap() {
 }
@@ -208,6 +211,20 @@ bool GLImageOzoneNativePixmap::ScheduleOverlayPlane(
                                        crop_rect);
 }
 
+void GLImageOzoneNativePixmap::Flush() {
+  if (!has_image_flush_external_)
+    return;
+
+  EGLDisplay display = GLSurfaceEGL::GetHardwareDisplay();
+  const EGLAttrib attribs[] = {
+      EGL_NONE,
+  };
+  if (!eglImageFlushExternalEXT(display, egl_image_, attribs)) {
+    LOG(ERROR) << "Failed to flush rendering";
+    return;
+  }
+}
+
 void GLImageOzoneNativePixmap::OnMemoryDump(
     base::trace_event::ProcessMemoryDump* pmd,
     uint64_t process_tracing_id,