Revert of Move UndoStack from Page to Editor

third_party/WebKit/Source/core/editing/commands/UndoStack.cpp

 /*
  * Copyright (C) 2006, 2007 Apple, Inc.  All rights reserved.
  * Copyright (C) 2012 Google, Inc.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 10 matching lines @@
  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "core/editing/commands/UndoStack.h"
 
 #include "core/dom/ContainerNode.h"
 #include "core/editing/commands/UndoStep.h"
+#include "platform/EventDispatchForbiddenScope.h"
 #include "wtf/TemporaryChange.h"
 
 namespace blink {
 
 // Arbitrary depth limit for the undo stack, to keep it from using
 // unbounded memory. This is the maximum number of distinct undoable
 // actions -- unbroken stretches of typed characters are coalesced
 // into a single action.
 static const size_t maximumUndoStackDepth = 1000;
 
@@ skipping 14 matching lines @@
     if (!m_inRedo)
         m_redoStack.clear();
     m_undoStack.append(step);
 }
 
 void UndoStack::registerRedoStep(UndoStep* step)
 {
     m_redoStack.append(step);
 }
 
+void UndoStack::didUnloadFrame(const LocalFrame& frame)
+{
+    EventDispatchForbiddenScope assertNoEventDispatch;
+    filterOutUndoSteps(m_undoStack, frame);
+    filterOutUndoSteps(m_redoStack, frame);
+}
+
+void UndoStack::filterOutUndoSteps(UndoStepStack& stack, const LocalFrame& frame)
+{
+    UndoStepStack newStack;
+    while (!stack.isEmpty()) {
+        UndoStep* step = stack.first().get();
+        if (!step->belongsTo(frame))
+            newStack.append(step);
+        stack.removeFirst();
+    }
+    stack.swap(newStack);
+}
+
 bool UndoStack::canUndo() const
 {
     return !m_undoStack.isEmpty();
 }
 
 bool UndoStack::canRedo() const
 {
     return !m_redoStack.isEmpty();
 }
 
@@ skipping 22 matching lines @@
     }
 }
 
 DEFINE_TRACE(UndoStack)
 {
     visitor->trace(m_undoStack);
     visitor->trace(m_redoStack);
 }
 
 } // namespace blink