Pass resourceless software mode in BeginFrameArgs

cc/trees/layer_tree_host_impl.cc

Index: cc/trees/layer_tree_host_impl.cc
diff --git a/cc/trees/layer_tree_host_impl.cc b/cc/trees/layer_tree_host_impl.cc
index 851885b80b3b9685c402507c93e96d2f54ffb7b8..3cae6fdb42d1c7b03eb2b4ee936fd90bf1555b68 100644
--- a/cc/trees/layer_tree_host_impl.cc
+++ b/cc/trees/layer_tree_host_impl.cc
@@ -244,6 +244,7 @@ LayerTreeHostImpl::LayerTreeHostImpl(
       device_scale_factor_(1.f),
       overhang_ui_resource_id_(0),
       overdraw_bottom_height_(0.f),
+      resourceless_software_draw_(false),
       device_viewport_valid_for_tile_management_(true),
       begin_impl_frame_interval_(BeginFrameArgs::DefaultInterval()),
       animation_registrar_(AnimationRegistrar::Create()),
@@ -549,8 +550,9 @@ void LayerTreeHostImpl::FrameData::AppendRenderPass(
   render_passes.push_back(render_pass.Pass());
 }
 
-static DrawMode GetDrawMode(OutputSurface* output_surface) {
-  if (output_surface->ForcedDrawToSoftwareDevice()) {
+static DrawMode GetDrawMode(bool resourceless_software,

[danakj, 2014/07/09 17:21:07]

how about making this not static, and stop passing things in, then we can make
this method public, and use that from LTI, instead of making the
resourceless_software_mode_ flag public, to avoid different ways of checking for
the same thing?

[boliu, 2014/07/09 20:59:50]

Done.

+                            OutputSurface* output_surface) {
+  if (resourceless_software) {
     return DRAW_MODE_RESOURCELESS_SOFTWARE;
   } else if (output_surface->context_provider()) {
     return DRAW_MODE_HARDWARE;
@@ -778,7 +780,8 @@ DrawResult LayerTreeHostImpl::CalculateRenderPasses(
 
   int layers_drawn = 0;
 
-  const DrawMode draw_mode = GetDrawMode(output_surface_.get());
+  const DrawMode draw_mode =
+      GetDrawMode(resourceless_software_draw_, output_surface_.get());
 
   LayerIteratorType end =
       LayerIteratorType::End(frame->render_surface_layer_list);
@@ -915,7 +918,7 @@ DrawResult LayerTreeHostImpl::CalculateRenderPasses(
   DCHECK(!frame->render_passes.empty());
 
   // Should only have one render pass in resourceless software mode.
-  if (output_surface_->ForcedDrawToSoftwareDevice())
+  if (resourceless_software_draw_)

[danakj, 2014/07/09 17:21:07]

can you change this to be based on the draw_mode, and can you move this into the
DCHECK so we don't pay for this when DCHECKs are off?

like DCHECK(draw_mode != RESOURCLESS || passes.size() == 1u) << passes.size();

[boliu, 2014/07/09 20:59:50]

Done.

     DCHECK_EQ(1u, frame->render_passes.size());
 
   return draw_result;
@@ -1305,14 +1308,17 @@ void LayerTreeHostImpl::SetExternalDrawConstraints(
     const gfx::Transform& transform,
     const gfx::Rect& viewport,
     const gfx::Rect& clip,
+    bool resourceless_software_draw,
     bool valid_for_tile_management) {
-  if (external_transform_ != transform || external_viewport_ != viewport) {
+  if (external_transform_ != transform || external_viewport_ != viewport ||
+      resourceless_software_draw_ != resourceless_software_draw) {

[brianderson, 2014/07/08 21:26:12]

Is this the part that fixes the bug?

Was the point of removing OutputSurface::ForcedDrawToSoftwareDevice just to
clean up code? Are ForcedDrawToSoftwareDevice and resourceless_software_draw_
equivalent?

[boliu, 2014/07/08 21:31:14]

Yes
Yes they are meant to be equivalent. It's more of a clean up. See the discussion
in crbug.com/391829

     active_tree_->set_needs_update_draw_properties();
   }
 
   external_transform_ = transform;
   external_viewport_ = viewport;
   external_clip_ = clip;
+  resourceless_software_draw_ = resourceless_software_draw;
   device_viewport_valid_for_tile_management_ = valid_for_tile_management;
 }
 
@@ -1462,10 +1468,11 @@ void LayerTreeHostImpl::DrawLayers(FrameData* frame,
   if (active_tree_->hud_layer()) {
     TRACE_EVENT0("cc", "DrawLayers.UpdateHudTexture");
     active_tree_->hud_layer()->UpdateHudTexture(
-        GetDrawMode(output_surface_.get()), resource_provider_.get());
+        GetDrawMode(resourceless_software_draw_, output_surface_.get()),

[danakj, 2014/07/09 17:21:07]

can you move this GetDrawMode up above the if statement, and use the draw_mode
below instead of resourceless_software_draw_?

[boliu, 2014/07/09 20:59:50]

Done.

+        resource_provider_.get());
   }
 
-  if (output_surface_->ForcedDrawToSoftwareDevice()) {
+  if (resourceless_software_draw_) {
     bool disable_picture_quad_image_filtering =
         IsCurrentlyScrolling() || needs_animate_layers();