aura: fix flashing when switching tabs rapidly

The test was wrong (hence triggerring the DCHECK): host_->is_hidden() doesn't say anything about the last compositor frame that may still be pending, and sending the ACK causes the renderer to possibly render to the "front" surface in fast hide/show/hide/show transitions.

--enable-ui-release-front-surface hides the effect, but it's visible without that flag.

BUG=None


Review URL: https://chromiumcodereview.appspot.com/10830322

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@151645 0039d316-1c4b-4281-b951-d872f2087c98

content/browser/renderer_host/render_widget_host_view_aura.cc

@@ -618,9 +618,8 @@ void RenderWidgetHostViewAura::AcceleratedSurfaceBuffersSwapped(
   surface_route_id_ = params_in_pixel.route_id;
   // If protection state changed, then this swap is stale. We must still ACK but
   // do not update current_surface_ since it may have been discarded.
-  if (host_->is_hidden() ||
-      (params_in_pixel.protection_state_id &&
-          params_in_pixel.protection_state_id != protection_state_id_)) {
+  if (params_in_pixel.protection_state_id &&
+      params_in_pixel.protection_state_id != protection_state_id_) {
     DCHECK(!current_surface_);
     if (!params_in_pixel.skip_ack)
       InsertSyncPointAndACK(params_in_pixel.route_id, gpu_host_id, NULL);
@@ -689,9 +688,8 @@ void RenderWidgetHostViewAura::AcceleratedSurfacePostSubBuffer(
   surface_route_id_ = params_in_pixel.route_id;
   // If visible state changed, then this PSB is stale. We must still ACK but
   // do not update current_surface_.
-  if (host_->is_hidden() ||
-      (params_in_pixel.protection_state_id &&
-          params_in_pixel.protection_state_id != protection_state_id_)) {
+  if (params_in_pixel.protection_state_id &&
+      params_in_pixel.protection_state_id != protection_state_id_) {
     DCHECK(!current_surface_);
     InsertSyncPointAndACK(params_in_pixel.route_id, gpu_host_id, NULL);
     return;