Previously, the active document's lifecycle was bound to
SessionHistoryEntry via DocumentState. The ownership chain was:
Navigable → SessionHistoryEntry → DocumentState → Document
This made it impossible to move SessionHistoryEntry to the UI process
(which cannot own DOM::Document). This commit decouples the two by
giving Navigable a direct m_active_document field that serves as the
authoritative source for active_document().
- Navigable owns m_active_document directly; active_document() reads
from it instead of going through the active session history entry.
- DocumentState no longer holds a Document pointer. Instead, it stores
a document_id for "same document?" checks. Same-document navigations
share a DocumentState and thus the same document_id, while
cross-document navigations create a new DocumentState with a new ID.
- A pending_document parameter is threaded through
finalize_a_cross_document_navigation → apply_the_push_or_replace →
apply_the_history_step so the newly created document reaches
activation without being stored on DocumentState.
- For traversal, the population output delivers the document.
A resolved_document is computed per continuation from either the
pending document, the population output, or the current active
document (for same-document traversals).
With apply_to() now self-contained (carrying its own replacement
DocumentState rather than reading from the live entry), the clone at
the traversal call site is no longer needed.
The clone previously served two purposes:
1. Input snapshot: freeze entry fields before deferred population.
Now solved by changing populate_session_history_entry_document() to
take explicit input parameters, snapshotted before the
deferred_invoke.
2. Output isolation: absorb apply_to() and post-population adjustments
without mutating the live entry during unload. Now solved by storing
the PopulateSessionHistoryEntryDocumentOutput on the continuation
state and deferring all mutations (including the origin-based
classic_history_api_state reset and navigable_target_name clear)
to after_potential_unload.
The post-population adjustments run unconditionally in
after_potential_unload, covering both the population path and the
non-population path (e.g. traversal to an already-populated error
entry).
Remove 11 heavy includes from Document.h that were only needed for
pointer/reference types (already forward-declared in Forward.h), and
extract the nested ViewportClient interface to a standalone header.
This reduces Document.h's recompilation cascade from ~1228 files to
~717 files (42% reduction). Headers like BrowsingContext.h that were
previously transitively included see even larger improvements (from
~1228 down to ~73 dependents).
This is required to store Content Security Policies, as their
Directives are implemented as subclasses with overridden virtual
functions. Thus, they cannot be stored as generic Directive classes, as
it'll lose the ability to call overridden functions when they are
copied.
Resulting in a massive rename across almost everywhere! Alongside the
namespace change, we now have the following names:
* JS::NonnullGCPtr -> GC::Ref
* JS::GCPtr -> GC::Ptr
* JS::HeapFunction -> GC::Function
* JS::CellImpl -> GC::Cell
* JS::Handle -> GC::Root
Now that the heap has no knowledge about a JavaScript realm and is
purely for managing the memory of the heap, it does not make sense
to name this function to say that it is a non-realm variant.
