Bug 1736484 - Fix new dead-code warnings with rust 1.57. r=gfx-reviewers,nical

Differential Revision: https://phabricator.services.mozilla.com/D128825

gfx/webrender_bindings/src/bindings.rs

@@ -1706,7 +1706,7 @@ pub extern "C" fn wr_window_new(
 #[no_mangle]
 pub unsafe extern "C" fn wr_api_free_error_msg(msg: *mut c_char) {
     if !msg.is_null() {
-        CString::from_raw(msg);
+        drop(CString::from_raw(msg));
     }
 }
 

gfx/wr/webrender/src/device/gl.rs

@@ -386,7 +386,6 @@ impl<T> Drop for VBO<T> {
 pub struct ExternalTexture {
     id: gl::GLuint,
     target: gl::GLuint,
-    swizzle: Swizzle,
     uv_rect: TexelRect,
 }
 
@@ -394,13 +393,11 @@ impl ExternalTexture {
     pub fn new(
         id: u32,
         target: ImageBufferKind,
-        swizzle: Swizzle,
         uv_rect: TexelRect,
     ) -> Self {
         ExternalTexture {
             id,
             target: get_gl_target(target),
-            swizzle,
             uv_rect,
         }
     }

gfx/wr/webrender/src/internal_types.rs

@@ -686,17 +686,7 @@ pub enum ResultMsg {
 }
 
 #[derive(Clone, Debug)]
-pub struct ResourceCacheError {
-    description: String,
-}
-
-impl ResourceCacheError {
-    pub fn new(description: String) -> ResourceCacheError {
-        ResourceCacheError {
-            description,
-        }
-    }
-}
+pub struct ResourceCacheError;
 
 /// Primitive metadata we pass around in a bunch of places
 #[derive(Copy, Clone, Debug)]

gfx/wr/webrender/src/profiler.rs

@@ -1429,9 +1429,6 @@ pub struct Counter {
     /// Incremented when the counter changes.
     change_indicator: u8,
 
-    /// Only used to check that the constants match the real index.
-    index: usize,
-
     graph: Option<Graph>,
 }
 
@@ -1442,7 +1439,6 @@ impl Counter {
             unit: descriptor.unit,
             show_as: descriptor.show_as,
             expected: descriptor.expected.clone(),
-            index: descriptor.index,
             value: std::f64::NAN,
             num_samples: 0,
             sum: 0.0,

gfx/wr/webrender/src/renderer/mod.rs

@@ -4272,7 +4272,6 @@ impl Renderer {
                     ExternalTexture::new(
                         texture_id,
                         texture_target,
-                        Swizzle::default(),
                         image.uv,
                     )
                 }
@@ -4287,7 +4286,6 @@ impl Renderer {
                     ExternalTexture::new(
                         0,
                         texture_target,
-                        Swizzle::default(),
                         image.uv,
                     )
                 }