Added pinch viewport offset to history item.

Source/core/frame/PinchViewport.cpp

 /*
  * Copyright (C) 2013 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 73 matching lines @@
     m_innerViewportContainerLayer->setSize(m_size);
 
     // Make sure we clamp the offset to within the new bounds.
     setLocation(m_offset);
 
     // Need to re-compute sizes for the overlay scrollbars.
     setupScrollbar(WebScrollbar::Horizontal);
     setupScrollbar(WebScrollbar::Vertical);
 }
 
+void PinchViewport::reset()
+{
+    setLocation(FloatPoint(0, 0));
+    setScale(1);
+}
+
 void PinchViewport::mainFrameDidChangeSize()
 {
     // In unit tests we may not have initialized the layer tree.
     if (m_innerViewportScrollLayer)
         m_innerViewportScrollLayer->setSize(contentsSize());
 
     // Make sure the viewport's offset is clamped within the newly sized main frame.
     setLocation(m_offset);
 }
 
@@ skipping 13 matching lines @@
 
     m_offset = clampedOffset;
 
     ScrollingCoordinator* coordinator = m_frameHost.page().scrollingCoordinator();
     ASSERT(coordinator);
     coordinator->scrollableAreaScrollLayerDidChange(this);
 }
 
 void PinchViewport::setScale(float scale)
 {
+    if (scale == m_scale)
+        return;
+
     m_scale = scale;
 
+    mainFrame()->loader().saveScrollState();
+
     // Old-style pinch sets scale here but we shouldn't call into the
     // clamping code below.
     if (!m_innerViewportScrollLayer)
         return;
 
     // Ensure we clamp so we remain within the bounds.
     setLocation(visibleRect().location());
+
+    // TODO: We should probably be calling scaleDidChange type functions here.

[aelias_OOO_until_Jul13, 2014/05/07 08:06:03]

Separate from this patch, but the only thing in you might need to call is
m_pageScaleConstraintsSet.setNeedsReset(false);  (which might come up in Android
scale initialization cases later).

+    // see Page::setPageScaleFactor.
 }
 
 // Modifies the top of the graphics layer tree to add layers needed to support
 // the inner/outer viewport fixed-position model for pinch zoom. When finished,
 // the tree will look like this (with * denoting added layers):
 //
 // *innerViewportContainerLayer (fixed pos container)
 //  +- *pageScaleLayer
 //  |   +- *innerViewportScrollLayer
 //  |       +-- overflowControlsHostLayer (root layer)
@@ skipping 171 matching lines @@
 
 void PinchViewport::invalidateScrollbarRect(Scrollbar*, const IntRect&)
 {
     // Do nothing. Pinch scrollbars live on the compositor thread and will
     // be updated when the viewport is synced to the CC.
 }
 
 void PinchViewport::setScrollOffset(const IntPoint& offset)
 {
     setLocation(offset);
+
+    mainFrame()->loader().saveScrollState();
 }
 
 GraphicsLayer* PinchViewport::layerForContainer() const
 {
     return m_innerViewportContainerLayer.get();
 }
 
 GraphicsLayer* PinchViewport::layerForScrolling() const
 {
     return m_innerViewportScrollLayer.get();
@@ skipping 44 matching lines @@
     } else if (graphicsLayer == m_overlayScrollbarVertical.get()) {
         name =  "Overlay Scrollbar Vertical Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace WebCore