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

cc/layers/picture_layer_impl.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/layers/picture_layer_impl.h"
 
 #include <algorithm>
 #include <limits>
 #include <set>
 
@@ skipping 627 matching lines @@
 }
 
 int PictureLayerImpl::GetSkewportExtrapolationLimitInContentPixels() const {
   return layer_tree_impl()
       ->settings()
       .skewport_extrapolation_limit_in_content_pixels;
 }
 
 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
     // default-tile-size.
     default_tile_size =
         gfx::Size(layer_tree_impl()->device_viewport_size().width(),
                   layer_tree_impl()->device_viewport_size().height() / 4);
   }
   default_tile_size.SetToMin(gfx::Size(max_texture_size, max_texture_size));
 
@@ skipping 100 matching lines @@
   gfx::Rect content_rect(content_bounds());
   float scale = MaximumTilingContentsScale();
   PictureLayerTilingSet::CoverageIterator iter(
       tilings_.get(), scale, content_rect, ideal_contents_scale_);
 
   // Mask resource not ready yet.
   if (!iter || !*iter)
     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();
   if (!tile_version.IsReadyToDraw() ||
       tile_version.mode() != ManagedTileState::TileVersion::RESOURCE_MODE)
     return 0;
 
   return tile_version.get_resource_id();
 }
 
@@ skipping 395 matching lines @@
       raster_contents_scale_ =
           std::max(raster_contents_scale_,
                    draw_properties().maximum_animation_contents_scale);
     } else {
       raster_contents_scale_ =
           std::max(raster_contents_scale_,
                    1.f * ideal_page_scale_ * ideal_device_scale_);
     }
   }
 
-  // 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;
   }
 
   float low_res_factor =
       layer_tree_impl()->settings().low_res_contents_scale_factor;
   low_res_raster_contents_scale_ = std::max(
       raster_contents_scale_ * low_res_factor,
       MinimumContentsScale());
 }
@@ skipping 560 matching lines @@
       PictureLayerTilingSet::TilingRange tiling_range = CurrentTilingRange();
       size_t current_tiling_range_offset = current_tiling_ - tiling_range.start;
       return tiling_range.end - 1 - current_tiling_range_offset;
     }
   }
   NOTREACHED();
   return 0;
 }
 
 }  // namespace cc