Stop relying on linking details of std’s default allocator

We’ve been bitten before by symbol names changing:
https://github.com/servo/heapsize/pull/46
and upstream is planning to stop using jemalloc by default:
https://github.com/rust-lang/rust/issues/33082#issuecomment-309781465

So use the (relatively) new `#[global_allocator]` attribute
to explicitly select the system allocator on Windows
and jemalloc (now in an external crate) on other platforms.
This choice matches current defaults.

1 files changed, 2 insertions, 2 deletions

diff --git a/components/script/script_thread.rs b/components/script/script_thread.rs
index e5a9a0401aa..991ec777315 100644
--- a/components/script/script_thread.rs
+++ b/components/script/script_thread.rs
@@ -73,7 +73,7 @@ use js::jsapi::{JSAutoCompartment, JSContext, JS_SetWrapObjectCallbacks};
 use js::jsapi::{JSTracer, SetWindowProxyClass};
 use js::jsval::UndefinedValue;
 use js::rust::Runtime;
-use malloc_size_of::{malloc_size_of, MallocSizeOfOps};
+use malloc_size_of::MallocSizeOfOps;
 use mem::malloc_size_of_including_self;
 use metrics::PaintTimeMetrics;
 use microtask::{MicrotaskQueue, Microtask};
@@ -1506,7 +1506,7 @@ impl ScriptThread {
         let mut reports = vec![];
         // Servo uses vanilla jemalloc, which doesn't have a
         // malloc_enclosing_size_of function.
-        let mut ops = MallocSizeOfOps::new(malloc_size_of, None, None);
+        let mut ops = MallocSizeOfOps::new(::servo_allocator::usable_size, None, None);
 
         for (_, document) in self.documents.borrow().iter() {
             let current_url = document.url();