Reland 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 15 matching lines @@
         UndoStep* step(back->get());
         m_redoStack.remove(back);
 
         DCHECK(!m_inRedo);
         TemporaryChange<bool> redoScope(m_inRedo, true);
         step->reapply();
         // reapply will call us back to push this command onto the undo stack.
     }
 }
 
+void UndoStack::clear()
+{
+    m_undoStack.clear();
+    m_redoStack.clear();
+}
+
 DEFINE_TRACE(UndoStack)
 {
     visitor->trace(m_undoStack);
     visitor->trace(m_redoStack);
 }
 
 } // namespace blink