devtools: Register frame actor before pause (#42844)

We need a map between frame actor ids (from devtools) and frame objects
(from debugger.js) to implement stepping hooks in the future.

To achieve this, we register the frame actor with a call to the devtools
before entering the event loop when the debugger is paused. Instead of
creating the frame actor in `handle_debugger_pause`, we create it
before.

Testing: It passes existing devtools tests
Part of: #36027

Signed-off-by: eri <eri@igalia.com>
Co-authored-by: atbrakhi <atbrakhi@igalia.com>

components/script_bindings/webidls/DebuggerInterruptEvent.webidl

@@ -10,11 +10,15 @@ interface DebuggerInterruptEvent : Event {};
 partial interface DebuggerGlobalScope {
     undefined pauseAndRespond(
         PipelineIdInit pipelineId,
-        PausedFrame result,
-        boolean is_breakpoint);
+        DOMString frameActorId,
+        boolean isBreakpoint);
+
+    DOMString? registerFrameActor(
+        PipelineIdInit pipelineId,
+        FrameInfo result);
 };
 
-dictionary PausedFrame {
+dictionary FrameInfo {
     required unsigned long column;
     required DOMString displayName;
     required unsigned long line;