cc: GPU rasterize tiles synchronously in PrepareToDraw

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 bb1be9856d093663f5533a2c4a6cff40c0a50cfd..90cf216cbdd0472445a477c51e172271fbd4ffb1 100644
--- a/cc/trees/layer_tree_host_impl.cc
+++ b/cc/trees/layer_tree_host_impl.cc
@@ -328,7 +328,7 @@ void LayerTreeHostImpl::CommitComplete() {
     // more lazily when needed prior to drawing.
     sync_tree()->UpdateDrawProperties();
     // Start working on newly created tiles immediately if needed.
-    if (tile_manager_ && tile_priorities_dirty_)
+    if (tile_manager_ && tile_priorities_dirty_ && !use_gpu_rasterization_)

[vmiura, 2014/11/20 02:27:11]

Remove check for use_gpu_rasterization_, as we check it in ManageTiles.

[vmiura, 2014/11/20 02:53:45]

I take that back, since we need to run the "else" part and activate right now.

       ManageTiles();
     else
       NotifyReadyToActivate();
@@ -402,11 +402,23 @@ void LayerTreeHostImpl::Animate(base::TimeTicks monotonic_time) {
   AnimateTopControls(monotonic_time);
 }
 
+void LayerTreeHostImpl::RasterizeTiles() {
+  if (!tile_manager_)
+    return;
+  if (!tile_priorities_dirty_)
+    return;
+
+  tile_priorities_dirty_ = false;
+  tile_manager_->RasterizeTiles(global_tile_state_);
+}
+
 void LayerTreeHostImpl::ManageTiles() {
   if (!tile_manager_)
     return;
   if (!tile_priorities_dirty_)
     return;
+  if (use_gpu_rasterization_)
+    return;
 
   tile_priorities_dirty_ = false;
   tile_manager_->ManageTiles(global_tile_state_);
@@ -1044,6 +1056,9 @@ DrawResult LayerTreeHostImpl::PrepareToDraw(FrameData* frame) {
   bool ok = active_tree_->UpdateDrawProperties();
   DCHECK(ok) << "UpdateDrawProperties failed during draw";
 
+  if (use_gpu_rasterization_)
+    RasterizeTiles();

[brianderson, 2014/11/20 02:40:19]

Should we only RasterizeTiles if draw_result == DRAW_SUCCESS at then end?

Alternatively, does it work to call RasterizeTiles in DrawLayers after the
NoDamage early out?

[reveman, 2014/11/20 15:20:59]

How you considered rasterizing at draw time instead? It would guarantee that
we're no rasterizing any tiles that are not needed for the frame.

[vmiura, 2014/11/20 18:28:57]

I put it here in the prototype as it needs to be done after
active_tree->UpdateDrawProperties() but before CalculateRenderPasses().

[reveman, 2014/11/20 19:07:54]

Why before CalculateRenderPasses()?

+
   frame->render_surface_layer_list = &active_tree_->RenderSurfaceLayerList();
   frame->render_passes.clear();
   frame->render_passes_by_id.clear();
@@ -1835,7 +1850,7 @@ void LayerTreeHostImpl::SetVisible(bool visible) {
 
   // Evict tiles immediately if invisible since this tab may never get another
   // draw or timer tick.
-  if (!visible_)
+  if (!visible_ && !use_gpu_rasterization_)

[vmiura, 2014/11/20 02:27:11]

Remove check for use_gpu_rasterization_, as we check it in ManageTiles.

     ManageTiles();
 
   if (!renderer_)