Auto merge of #23816 - marmeladema:issue-20377, r=jdm

Wrapping unsafe raw JSContext pointers in a safe struct. Part 1.

Wrapping unsafe raw JSContext pointers in a safe struct. Issue #20377.

---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `___` with appropriate data: -->
- [x] create a struct JSContext(*mut jsapi::JSContext) type
- [x] implement Deref for this new type so it's easy to obtain the inner context pointer
- [x] add an unsafe from_ptr static method that returns a new instance of the type
- [x] start by changing various Argument uses in CodegenRust.py for python classes that inherit from CGAbstractMethod
- [x] convert the python code that interacts with CGClass (CGCallback, CGCallbackFunction, CGCallbackFunctionImpl, CGCallbackInterface) and any rust code that interacts with it
- [x] update CGDictionary and any rust code that interacts with it
- [x] make the code generator declare trait methods that accept the new type instead of *mut JSContext (CGInterfaceTrait)
- [x] modify GlobalScope::get_cx to return a SafeJSContext

<!-- Also, please make sure that "Allow edits from maintainers" checkbox is checked, so that we can help you if you get stuck somewhere along the way.-->

<!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. -->

<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/23816)
<!-- Reviewable:end -->

1 files changed, 7 insertions, 7 deletions

diff --git a/components/script/webdriver_handlers.rs b/components/script/webdriver_handlers.rs
index ab08c0efe7d..c8aad9a6b4c 100644
--- a/components/script/webdriver_handlers.rs
+++ b/components/script/webdriver_handlers.rs
@@ -145,11 +145,11 @@ pub fn handle_execute_script(
         Some(window) => {
             let result = unsafe {
                 let cx = window.get_cx();
-                rooted!(in(cx) let mut rval = UndefinedValue());
+                rooted!(in(*cx) let mut rval = UndefinedValue());
                 window
                     .upcast::<GlobalScope>()
                     .evaluate_js_on_global_with_result(&eval, rval.handle_mut());
-                jsval_to_webdriver(cx, rval.handle())
+                jsval_to_webdriver(*cx, rval.handle())
             };
 
             reply.send(result).unwrap();
@@ -171,7 +171,7 @@ pub fn handle_execute_async_script(
         Some(window) => {
             let cx = window.get_cx();
             window.set_webdriver_script_chan(Some(reply));
-            rooted!(in(cx) let mut rval = UndefinedValue());
+            rooted!(in(*cx) let mut rval = UndefinedValue());
             window
                 .upcast::<GlobalScope>()
                 .evaluate_js_on_global_with_result(&eval, rval.handle_mut());
@@ -725,21 +725,21 @@ pub fn handle_get_property(
             Some(node) => {
                 let cx = documents.find_document(pipeline).unwrap().window().get_cx();
 
-                rooted!(in(cx) let mut property = UndefinedValue());
+                rooted!(in(*cx) let mut property = UndefinedValue());
                 match unsafe {
                     get_property_jsval(
-                        cx,
+                        *cx,
                         node.reflector().get_jsobject(),
                         &name,
                         property.handle_mut(),
                     )
                 } {
-                    Ok(_) => match unsafe { jsval_to_webdriver(cx, property.handle()) } {
+                    Ok(_) => match unsafe { jsval_to_webdriver(*cx, property.handle()) } {
                         Ok(property) => Ok(property),
                         Err(_) => Ok(WebDriverJSValue::Undefined),
                     },
                     Err(error) => {
-                        unsafe { throw_dom_exception(cx, &node.reflector().global(), error) };
+                        unsafe { throw_dom_exception(*cx, &node.reflector().global(), error) };
                         Ok(WebDriverJSValue::Undefined)
                     },
                 }