webrender: Remove unnecessary mut references.

webrender/src/glyph_rasterizer.rs

@@ -777,7 +777,7 @@ impl GlyphRasterizer {
                     GlyphRasterResult::Bitmap(glyph) => {
                         assert_eq!((glyph.left.fract(), glyph.top.fract()), (0.0, 0.0));
                         let mut texture_cache_handle = TextureCacheHandle::new();
-                        texture_cache.request(&mut texture_cache_handle, gpu_cache);
+                        texture_cache.request(&texture_cache_handle, gpu_cache);
                         texture_cache.update(
                             &mut texture_cache_handle,
                             ImageDescriptor {

webrender/src/render_task.rs

@@ -932,7 +932,7 @@ impl RenderTaskCache {
                               });
 
         // Check if this texture cache handle is valid.
-        if texture_cache.request(&mut cache_entry.handle, gpu_cache) {
+        if texture_cache.request(&cache_entry.handle, gpu_cache) {
             // Invoke user closure to get render task chain
             // to draw this into the texture cache.
             let (render_task_id, is_opaque) = try!(f(render_tasks));

webrender/src/resource_cache.rs

@@ -597,7 +597,7 @@ impl ResourceCache {
         };
 
         let needs_upload = self.texture_cache
-            .request(&mut entry.as_mut().unwrap().texture_cache_handle, gpu_cache);
+            .request(&entry.as_ref().unwrap().texture_cache_handle, gpu_cache);
 
         if !needs_upload && !needs_update {
             return;
@@ -858,7 +858,7 @@ impl ResourceCache {
         debug_assert_eq!(self.state, State::Idle);
         self.state = State::AddResources;
         self.texture_cache.begin_frame(frame_id);
-        self.cached_glyphs.begin_frame(&mut self.texture_cache, &self.cached_render_tasks);
+        self.cached_glyphs.begin_frame(&self.texture_cache, &self.cached_render_tasks);
         self.cached_render_tasks.begin_frame(&mut self.texture_cache);
         self.current_frame_id = frame_id;
     }