Use transform_rect in prim_store.rs

Instead of duplicating the functionality of transform_rect in
get_local_bounding_rect, just use the function from utils.rs.

webrender/src/prim_store.rs

@@ -2,12 +2,12 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use api::{BorderRadius, BuiltDisplayList, ColorF, ComplexClipRegion, DeviceIntRect};
-use api::{DevicePoint, ExtendMode, FontRenderMode, GlyphInstance, GlyphKey};
-use api::{GradientStop, ImageKey, ImageRendering, ItemRange, ItemTag, LayerPoint, LayerRect};
-use api::{ClipMode, LayerSize, LayerVector2D, LayerToWorldTransform, LineOrientation, LineStyle};
-use api::{ClipAndScrollInfo, PremultipliedColorF, TileOffset, WorldToLayerTransform};
-use api::{ClipId, LayerTransform, PipelineId, YuvColorSpace, YuvFormat};
+use api::{BorderRadius, BuiltDisplayList, ClipAndScrollInfo, ClipId, ClipMode, ColorF};
+use api::{ComplexClipRegion, DeviceIntRect, DevicePoint, ExtendMode, FontRenderMode};
+use api::{GlyphInstance, GlyphKey, GradientStop, ImageKey, ImageRendering, ItemRange, ItemTag};
+use api::{LayerPoint, LayerRect, LayerSize, LayerToWorldTransform, LayerTransform, LayerVector2D};
+use api::{LineOrientation, LineStyle, PipelineId, PremultipliedColorF, TileOffset};
+use api::{WorldToLayerTransform, YuvColorSpace, YuvFormat};
 use border::BorderCornerInstance;
 use clip_scroll_tree::{CoordinateSystemId, ClipScrollTree};
 use clip::{ClipSource, ClipSourcesHandle, ClipStore};
@@ -1854,13 +1854,13 @@ impl PrimitiveStore {
                     profile_counters.visible_primitives.inc();
 
                     if let Some(ref matrix) = original_relative_transform {
-                        let bounds = get_local_bounding_rect(&prim_local_rect, matrix);
+                        let bounds = matrix.transform_rect(&prim_local_rect);
                         result.local_rect_in_original_parent_space =
                             result.local_rect_in_original_parent_space.union(&bounds);
                     }
 
                     if let Some(ref matrix) = parent_relative_transform {
-                        let bounds = get_local_bounding_rect(&prim_local_rect, matrix);
+                        let bounds = matrix.transform_rect(&prim_local_rect);
                         result.local_rect_in_actual_parent_space =
                             result.local_rect_in_actual_parent_space.union(&bounds);
                     }
@@ -1897,32 +1897,6 @@ impl InsideTest<ComplexClipRegion> for ComplexClipRegion {
     }
 }
 
-fn get_local_bounding_rect(
-    local_rect: &LayerRect,
-    matrix: &LayerTransform
-) -> LayerRect {
-    let vertices = [
-        matrix.transform_point3d(&local_rect.origin.to_3d()),
-        matrix.transform_point3d(&local_rect.bottom_left().to_3d()),
-        matrix.transform_point3d(&local_rect.bottom_right().to_3d()),
-        matrix.transform_point3d(&local_rect.top_right().to_3d()),
-    ];
-
-    let mut x0 = vertices[0].x;
-    let mut y0 = vertices[0].y;
-    let mut x1 = vertices[0].x;
-    let mut y1 = vertices[0].y;
-
-    for v in &vertices[1..] {
-        x0 = x0.min(v.x);
-        y0 = y0.min(v.y);
-        x1 = x1.max(v.x);
-        y1 = y1.max(v.y);
-    }
-
-    LayerRect::new(LayerPoint::new(x0, y0), LayerSize::new(x1 - x0, y1 - y0))
-}
-
 fn create_nine_patch(
     local_rect: &LayerRect,
     local_clip_rect: &LayerRect,