Auto merge of #9123 - karyon:clippy_cleanup, r=Manishearth

Fix a bunch of clippy lints

This fixes about 130 clippy lints. Let me know if i should split up the commit.

I wasn't sure about some of the changes, especially map_or instead of map(...).unwrap_or(...) and if let instead of single arm match were not always a strict improvement in my opinion, but i'll leave that decision to the reviewer :)

There are about 150 lints left which i thought were clippy bugs or i didn't know how to fix.

cc @Manishearth

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components/gfx/display_list/mod.rs

@@ -941,7 +941,7 @@ impl StackingContextLayerCreator {
             return Some(LayerInfo::new(layer.id, ScrollPolicy::Scrollable, None));
         }
 
-        return self.last_child_layer_info;
+        self.last_child_layer_info
     }
 
     #[inline]

components/gfx/font_cache_task.rs

@@ -39,7 +39,7 @@ impl FontTemplates {
     }
 
     /// Find a font in this family that matches a given descriptor.
-    fn find_font_for_style<'a>(&'a mut self, desc: &FontTemplateDescriptor, fctx: &FontContextHandle)
+    fn find_font_for_style(&mut self, desc: &FontTemplateDescriptor, fctx: &FontContextHandle)
                                -> Option<Arc<FontTemplateData>> {
         // TODO(Issue #189): optimize lookup for
         // regular/bold/italic/bolditalic with fixed offsets and a
@@ -251,7 +251,7 @@ impl FontCache {
         }
     }
 
-    fn find_font_in_local_family<'a>(&'a mut self, family_name: &LowercaseString, desc: &FontTemplateDescriptor)
+    fn find_font_in_local_family(&mut self, family_name: &LowercaseString, desc: &FontTemplateDescriptor)
                                 -> Option<Arc<FontTemplateData>> {
         // TODO(Issue #188): look up localized font family names if canonical name not found
         // look up canonical name
@@ -275,14 +275,13 @@ impl FontCache {
         }
     }
 
-    fn find_font_in_web_family<'a>(&'a mut self, family: &FontFamily, desc: &FontTemplateDescriptor)
+    fn find_font_in_web_family(&mut self, family: &FontFamily, desc: &FontTemplateDescriptor)
                                 -> Option<Arc<FontTemplateData>> {
         let family_name = LowercaseString::new(family.name());
 
         if self.web_families.contains_key(&family_name) {
             let templates = self.web_families.get_mut(&family_name).unwrap();
-            let maybe_font = templates.find_font_for_style(desc, &self.font_context);
-            maybe_font
+            templates.find_font_for_style(desc, &self.font_context)
         } else {
             None
         }

components/gfx/platform/freetype/font.rs

@@ -166,12 +166,12 @@ impl FontHandleMethods for FontHandle {
         assert!(!self.face.is_null());
         unsafe {
             let idx = FT_Get_Char_Index(self.face, codepoint as FT_ULong);
-            return if idx != 0 as FT_UInt {
+            if idx != 0 as FT_UInt {
                 Some(idx as GlyphId)
             } else {
                 debug!("Invalid codepoint: {}", codepoint);
                 None
-            };
+            }
         }
     }
 
@@ -196,10 +196,10 @@ impl FontHandleMethods for FontHandle {
                 let advance = (*slot).metrics.horiAdvance;
                 debug!("h_advance for {} is {}", glyph, advance);
                 let advance = advance as i32;
-                return Some(fixed_to_float_ft(advance) as FractionalPixel);
+                Some(fixed_to_float_ft(advance) as FractionalPixel)
             } else {
                 debug!("Unable to load glyph {}. reason: {}", glyph, res);
-                return None;
+                None
             }
         }
     }
@@ -239,8 +239,7 @@ impl FontHandleMethods for FontHandle {
 
         let average_advance = self.glyph_index('0')
                                   .and_then(|idx| self.glyph_h_advance(idx))
-                                  .map(|advance| self.font_units_to_au(advance))
-                                  .unwrap_or(max_advance);
+                                  .map_or(max_advance, |advance| self.font_units_to_au(advance));
 
         let metrics = FontMetrics {
             underline_size:   underline_size,
@@ -258,7 +257,7 @@ impl FontHandleMethods for FontHandle {
         };
 
         debug!("Font metrics (@{}px): {:?}", em_size.to_f32_px(), metrics);
-        return metrics;
+        metrics
     }
 
     fn table_for_tag(&self, tag: FontTableTag) -> Option<Box<FontTable>> {
@@ -310,6 +309,6 @@ impl<'a> FontHandle {
         // If this isn't true then we're scaling one of the axes wrong
         assert!(metrics.x_ppem == metrics.y_ppem);
 
-        return Au::from_f64_px(value * x_scale);
+        Au::from_f64_px(value * x_scale)
     }
 }