WebContent process keeps session history entries for pages we have
navigated away from. Before this change, those entries could prevent GC
objects (e.g. PolicyContainer and its CSP PolicyList) from being
collected, since the GC-allocated SHE/DocumentState held live GC::Ref
pointers into the heap.
By making both classes RefCounted and storing SerializedPolicyContainer
instead of a live PolicyContainer, history entries no longer keep alive
any GC objects. This eliminates the leak and is also a step toward
moving the session history entry tree to the UI process.
Remove m_original_source_browsing_context, m_browsing_context_name, and
m_policy_container along with their getters and setters, as they have no
callers outside the class itself.
This also adds a missing include for JS::call in WebDriver/JSON.cpp,
which was previously provided transitively through the removed headers.
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).
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
