Add style_traits crate to improve crate separation,

closes #7353

components/msg/Cargo.toml

@@ -7,15 +7,15 @@ authors = ["The Servo Project Developers"]
 name = "msg"
 path = "lib.rs"
 
-[dependencies.style]
-path = "../style"
-
 [dependencies.util]
 path = "../util"
 
 [dependencies.canvas_traits]
 path = "../canvas_traits"
 
+[dependencies.style_traits]
+path = "../style_traits"
+
 [dependencies.azure]
 git = "https://github.com/servo/rust-azure"
 
@@ -56,4 +56,3 @@ core-foundation = "0.1"
 
 [target.x86_64-apple-darwin.dependencies.io-surface]
 git = "https://github.com/servo/io-surface-rs"
-

components/msg/constellation_msg.rs

@@ -18,7 +18,7 @@ use offscreen_gl_context::GLContextAttributes;
 use png::Image;
 use std::collections::HashMap;
 use std::sync::mpsc::{channel, Sender, Receiver};
-use style::viewport::ViewportConstraints;
+use style_traits::viewport::ViewportConstraints;
 use url::Url;
 use util::cursor::Cursor;
 use util::geometry::{PagePx, ViewportPx};

components/msg/lib.rs

@@ -18,7 +18,7 @@ extern crate rustc_serialize;
 extern crate serde;
 extern crate util;
 extern crate url;
-extern crate style;
+extern crate style_traits;
 
 #[cfg(target_os = "macos")]
 extern crate core_foundation;