cc: Early out sooner in UpdateTilePriorities when !CanHaveTilings().

cc/layers/picture_layer_impl.cc

Index: cc/layers/picture_layer_impl.cc
diff --git a/cc/layers/picture_layer_impl.cc b/cc/layers/picture_layer_impl.cc
index eabfdc69b844f609b90de612f2c735facf69f134..55f4c39dddb9395856977b948ec83ee3a35332d8 100644
--- a/cc/layers/picture_layer_impl.cc
+++ b/cc/layers/picture_layer_impl.cc
@@ -390,14 +390,6 @@ void PictureLayerImpl::UpdateTilePriorities() {
   TRACE_EVENT0("cc", "PictureLayerImpl::UpdateTilePriorities");
 
   DoPostCommitInitializationIfNeeded();
-  UpdateIdealScales();
-  // TODO(sohanjg): Avoid needlessly update priorities when syncing to a
-  // non-updated tree which will then be updated immediately afterwards.
-  should_update_tile_priorities_ = true;
-  if (CanHaveTilings()) {
-    ManageTilings(draw_properties().screen_space_transform_is_animating,
-                  draw_properties().maximum_animation_contents_scale);
-  }
 
   if (layer_tree_impl()->device_viewport_valid_for_tile_management()) {
     visible_rect_for_tile_priority_ = visible_content_rect();
@@ -405,6 +397,23 @@ void PictureLayerImpl::UpdateTilePriorities() {
     screen_space_transform_for_tile_priority_ = screen_space_transform();
   }
 
+  if (!CanHaveTilings()) {
+    ideal_page_scale_ = 0.f;
+    ideal_device_scale_ = 0.f;
+    ideal_contents_scale_ = 0.f;
+    ideal_source_scale_ = 0.f;
+    SanityCheckTilingState();
+    return;
+  }
+
+  // TODO(sohanjg): Avoid needlessly update priorities when syncing to a
+  // non-updated tree which will then be updated immediately afterwards.
+  should_update_tile_priorities_ = true;
+
+  UpdateIdealScales();
+  ManageTilings(draw_properties().screen_space_transform_is_animating,
+                draw_properties().maximum_animation_contents_scale);
+
   if (!tilings_->num_tilings())
     return;
 
@@ -1165,7 +1174,7 @@ void PictureLayerImpl::CleanUpTilingsOnActiveLayer(
   float twin_low_res_scale = 0.f;
 
   PictureLayerImpl* twin = twin_layer_;
-  if (twin) {
+  if (twin && twin->CanHaveTilings()) {
     min_acceptable_high_res_scale = std::min(
         min_acceptable_high_res_scale,
         std::min(twin->raster_contents_scale_, twin->ideal_contents_scale_));
@@ -1288,15 +1297,6 @@ float PictureLayerImpl::MaximumTilingContentsScale() const {
 }
 
 void PictureLayerImpl::UpdateIdealScales() {
-  if (!CanHaveTilings()) {

[enne (OOO), 2014/06/18 23:08:02]

I kind of liked this code being in UpdateIdealScales, because then the caller
doesn't have to think about whether something can or cannot have tilings.  I
think you can still call it prior to early-outting and setting
should_update_tile_priorities=true.

[danakj, 2014/06/19 01:03:52]

ok, i can leave it there. I liked the idea of moving it because
a) removed one check for CanHaveTilings() meaning we don't have this agreement
needed between UpdateTilePrios and UpdateIdealScales anymore regarding
CanHaveTilings()
b) no early out needed in UpdateIdealScales made it simpler in my mind.

If those things don't convince you, I'm uploading a CL without moving this, so
we can do that.

-    ideal_page_scale_ = draw_properties().page_scale_factor;
-    ideal_device_scale_ = draw_properties().device_scale_factor;
-    ideal_contents_scale_ = draw_properties().ideal_contents_scale;
-    ideal_source_scale_ =
-        ideal_contents_scale_ / ideal_page_scale_ / ideal_device_scale_;
-    return;
-  }
-
   float min_contents_scale = MinimumContentsScale();
   DCHECK_GT(min_contents_scale, 0.f);
   float min_page_scale = layer_tree_impl()->min_page_scale_factor();