cc: Don't make tiles for mask layers that are too big for a texture.

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 763f05e1e33ccaac7a3351bf28883ace51575183..32b629dbe45c3f81d720bfad9091227707026ade 100644
--- a/cc/layers/picture_layer_impl.cc
+++ b/cc/layers/picture_layer_impl.cc
@@ -645,16 +645,16 @@ int PictureLayerImpl::GetSkewportExtrapolationLimitInContentPixels() const {
 
 gfx::Size PictureLayerImpl::CalculateTileSize(
     const gfx::Size& content_bounds) const {
-  if (is_mask_) {
-    int max_size = layer_tree_impl()->MaxTextureSize();
-    return gfx::Size(
-        std::min(max_size, content_bounds.width()),
-        std::min(max_size, content_bounds.height()));
-  }
-
   int max_texture_size =
       layer_tree_impl()->resource_provider()->max_texture_size();

[vmpstr, 2014/09/05 17:44:57]

Is this max_texture_size the same as layer_tree_impl()->MaxTextureSize (which
was returned before) I guess it's the same since MaxTextureSize went away.

[danakj, 2014/09/05 22:09:52]

Ya. RendererCaps is set based on the value from ResourceProvider (it's weird we
have this in 2 places)

 
+  if (is_mask_) {
+    if (content_bounds.width() > max_texture_size ||

[vmpstr, 2014/09/05 17:44:57]

Can you please drop a comment here saying that "blah blah tiled mask blah no".

[danakj, 2014/09/05 22:09:51]

Done.

+        content_bounds.height() > max_texture_size)
+      return gfx::Size();
+    return content_bounds;
+  }
+
   gfx::Size default_tile_size = layer_tree_impl()->settings().default_tile_size;
   if (layer_tree_impl()->use_gpu_rasterization()) {
     // TODO(ernstm) crbug.com/365877: We need a unified way to override the
@@ -775,8 +775,9 @@ ResourceProvider::ResourceId PictureLayerImpl::ContentsResourceId() const {
     return 0;
 
   // Masks only supported if they fit on exactly one tile.
-  if (iter.geometry_rect() != content_rect)
-    return 0;
+  DCHECK(iter.geometry_rect() == content_rect)
+      << "iter rect " << iter.geometry_rect().ToString() << " content rect "
+      << content_rect.ToString();
 
   const ManagedTileState::TileVersion& tile_version =
       iter->GetTileVersionForDrawing();
@@ -1192,13 +1193,14 @@ void PictureLayerImpl::RecalculateRasterScales() {
     }
   }
 
-  // If this layer would only create one tile at this content scale,
+  // If this layer would create zero or one tiles at this content scale,
   // don't create a low res tiling.
   gfx::Size content_bounds =
       gfx::ToCeiledSize(gfx::ScaleSize(bounds(), raster_contents_scale_));
   gfx::Size tile_size = CalculateTileSize(content_bounds);
-  if (tile_size.width() >= content_bounds.width() &&
-      tile_size.height() >= content_bounds.height()) {
+  bool tile_covers_bounds = tile_size.width() >= content_bounds.width() &&
+                            tile_size.height() >= content_bounds.height();
+  if (tile_size.IsEmpty() || tile_covers_bounds) {
     low_res_raster_contents_scale_ = raster_contents_scale_;
     return;
   }