[in-place weak refs] Remove WeakCell helpers from CSA

BUG=v8:7308

Change-Id: Icdbf7e786ce4ac19d73ab8e69bb57c0b19271b33
Reviewed-on: https://chromium-review.googlesource.com/1167043Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Marja Hölttä <marja@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54969}

src/code-stub-assembler.cc

@@ -1807,23 +1807,6 @@ Node* CodeStubAssembler::LoadJSValueValue(Node* object) {
   return LoadObjectField(object, JSValue::kValueOffset);
 }
 
-TNode<Object> CodeStubAssembler::LoadWeakCellValueUnchecked(
-    SloppyTNode<HeapObject> weak_cell) {
-  CSA_ASSERT(this, IsStrongHeapObject(weak_cell));
-  // TODO(ishell): fix callers.
-  return LoadObjectField(weak_cell, WeakCell::kValueOffset);
-}
-
-TNode<Object> CodeStubAssembler::LoadWeakCellValue(
-    SloppyTNode<WeakCell> weak_cell, Label* if_cleared) {
-  CSA_ASSERT(this, IsWeakCell(weak_cell));
-  TNode<Object> value = LoadWeakCellValueUnchecked(weak_cell);
-  if (if_cleared != nullptr) {
-    GotoIf(WordEqual(value, IntPtrConstant(0)), if_cleared);
-  }
-  return value;
-}
-
 void CodeStubAssembler::DispatchMaybeObject(TNode<MaybeObject> maybe_object,
                                             Label* if_smi, Label* if_cleared,
                                             Label* if_weak, Label* if_strong,

src/code-stub-assembler.h

@@ -914,10 +914,6 @@ class V8_EXPORT_PRIVATE CodeStubAssembler : public compiler::CodeAssembler {
   Node* PointerToSeqStringData(Node* seq_string);
   // Load value field of a JSValue object.
   Node* LoadJSValueValue(Node* object);
-  // Load value field of a WeakCell object.
-  TNode<Object> LoadWeakCellValueUnchecked(SloppyTNode<HeapObject> weak_cell);
-  TNode<Object> LoadWeakCellValue(SloppyTNode<WeakCell> weak_cell,
-                                  Label* if_cleared = nullptr);
 
   // Figures out whether the value of maybe_object is:
   // - a SMI (jump to "if_smi", "extracted" will be the SMI value)