Auto merge of #13646 - asajeffrey:script-lookup-iframes-by-frameid, r=ConnorGBrewster

Script lookup iframes by frameid

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Lookup iframes by `FrameId` rather than `PipelineId`. This should make lookup much more reliable, since the frame id doesn't change.

cc @ConnorGBrewster @aneeshusa
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- [X] `./mach test-tidy` does not report any errors
- [X] These changes do not require tests because refactoring

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1 files changed, 3 insertions, 4 deletions

diff --git a/components/script_traits/script_msg.rs b/components/script_traits/script_msg.rs
index 82b7af96f81..b73be67c023 100644
--- a/components/script_traits/script_msg.rs
+++ b/components/script_traits/script_msg.rs
@@ -83,10 +83,9 @@ pub enum ScriptMsg {
     /// A new load has been requested, with an option to replace the current entry once loaded
     /// instead of adding a new entry.
     LoadUrl(PipelineId, LoadData, bool),
-    /// Dispatch a mozbrowser event to a given iframe,
-    /// or to the window if no subpage id is provided.
-    /// First PipelineId is for the parent, second PipelineId is for the actual pipeline.
-    MozBrowserEvent(PipelineId, Option<PipelineId>, MozBrowserEvent),
+    /// Dispatch a mozbrowser event to the parent of this pipeline.
+    /// The first PipelineId is for the parent, the second is for the originating pipeline.
+    MozBrowserEvent(PipelineId, PipelineId, MozBrowserEvent),
     /// HTMLIFrameElement Forward or Back traversal.
     TraverseHistory(Option<PipelineId>, TraversalDirection),
     /// Gets the length of the joint session history from the constellation.