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..2e9322704475d7f2cbcf1a05d38dc89a3118c100 100644
--- a/ui/gl/gl_image_ozone_native_pixmap.cc
+++ b/ui/gl/gl_image_ozone_native_pixmap.cc
@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 #include "ui/gfx/buffer_format_util.h"
+#include "ui/gl/gl_fence.h"
 #include "ui/gl/gl_image_ozone_native_pixmap.h"
 #include "ui/gl/gl_surface_egl.h"
 
@@ -204,6 +205,7 @@ bool GLImageOzoneNativePixmap::ScheduleOverlayPlane(
     const gfx::Rect& bounds_rect,
     const gfx::RectF& crop_rect) {
   DCHECK(pixmap_);
+

[reveman, 2016/07/11 18:59:06]

nit: no need to add this blank line

   return pixmap_->ScheduleOverlayPlane(widget, z_order, transform, bounds_rect,
                                        crop_rect);
 }
@@ -247,4 +249,19 @@ unsigned GLImageOzoneNativePixmap::GetInternalFormatForTesting(
   return GL_NONE;
 }
 
+void GLImageOzoneNativePixmap::Flush() {

[reveman, 2016/07/11 18:59:06]

nit: move below ScheduleOverlayPlane

+  if (GLSurfaceEGL::HasEGLExtension("EGL_EXT_image_flush_external")) {

[piman, 2016/07/11 16:06:26]

nit: parsing strings on every frame seems a bit unfortunate. Can we check this
at creation time and keep in a field?

+    EGLDisplay display = GLSurfaceEGL::GetHardwareDisplay();
+    const EGLAttrib attribs[] = {
+        EGL_NONE,
+    };
+    if (!eglImageFlushExternalEXT(display, egl_image_, attribs)) {
+      LOG(ERROR) << "Failed to flush rendering";
+      return;
+    }
+  }
+
+  return;

[reveman, 2016/07/11 18:59:06]

nit: remove unnecessary return statement

+}
+
 }  // namespace gl