Reset to initial page scale in additional scenarios.

Source/web/PageScaleConstraintsSet.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 48 matching lines @@
 
     m_constraintsDirty = true;
 }
 
 void PageScaleConstraintsSet::setUserAgentConstraints(const PageScaleConstraints& userAgentConstraints)
 {
     m_userAgentConstraints = userAgentConstraints;
     m_constraintsDirty = true;
 }
 
+PageScaleConstraints PageScaleConstraintsSet::computeConstraintsStack() const
+{
+    PageScaleConstraints constraints = defaultConstraints();
+    constraints.overrideWith(m_pageDefinedConstraints);
+    constraints.overrideWith(m_userAgentConstraints);
+    return constraints;
+}
+
 void PageScaleConstraintsSet::computeFinalConstraints()
 {
-    m_finalConstraints = defaultConstraints();
-    m_finalConstraints.overrideWith(m_pageDefinedConstraints);
-    m_finalConstraints.overrideWith(m_userAgentConstraints);
+    m_finalConstraints = computeConstraintsStack();
 
     m_constraintsDirty = false;
 }
 
 void PageScaleConstraintsSet::adjustFinalConstraintsToContentsSize(IntSize viewSize, IntSize contentsSize, int nonOverlayScrollbarWidth)
 {
     m_finalConstraints.fitToContentsWidth(contentsSize.width(), viewSize.width() - nonOverlayScrollbarWidth);
 }
 
 void PageScaleConstraintsSet::setNeedsReset(bool needsReset)
 {
     m_needsReset = needsReset;
     if (needsReset)
         m_constraintsDirty = true;
 }
 
 void PageScaleConstraintsSet::didChangeContentsSize(IntSize contentsSize, float pageScaleFactor)
 {
-    // If a large fixed-width element expanded the size of the document
-    // late in loading and our initial scale is not constrained, reset the
-    // page scale factor to the new minimum scale.
+    // If a large fixed-width element expanded the size of the document late in
+    // loading and our initial scale is not set (or set to be less than the last
+    // minimum scale), reset the page scale factor to the new initial scale.
     if (contentsSize.width() > m_lastContentsWidth
         && pageScaleFactor == finalConstraints().minimumScale
-        && userAgentConstraints().initialScale == -1 && pageDefinedConstraints().initialScale == -1)
+        && computeConstraintsStack().initialScale < finalConstraints().minimumScale)
         setNeedsReset(true);
 
     m_constraintsDirty = true;
     m_lastContentsWidth = contentsSize.width();
 }
 
 static float computeDeprecatedTargetDensityDPIFactor(const ViewportDescription& description, float deviceScaleFactor)
 {
     if (description.deprecatedTargetDensityDPI == ViewportDescription::ValueDeviceDPI)
         return 1.0f / deviceScaleFactor;
@@ skipping 53 matching lines @@
             const float nonWideScale = description.zoom < 1 && !description.maxWidth.isViewportPercentage() ? -1 : oldInitialScale;
             adjustedLayoutSizeWidth = getLayoutWidthForNonWideViewport(viewSize, nonWideScale) / targetDensityDPIFactor;
             if (description.zoom < 1) {
                 m_pageDefinedConstraints.initialScale = targetDensityDPIFactor;
                 m_pageDefinedConstraints.minimumScale = std::min<float>(m_pageDefinedConstraints.minimumScale, m_pageDefinedConstraints.initialScale);
                 m_pageDefinedConstraints.maximumScale = std::max<float>(m_pageDefinedConstraints.maximumScale, m_pageDefinedConstraints.initialScale);
             }
         }
     }
 
-    if (oldInitialScale != m_pageDefinedConstraints.initialScale && m_pageDefinedConstraints.initialScale != -1)
-        setNeedsReset(true);
-
     if (adjustedLayoutSizeWidth != m_pageDefinedConstraints.layoutSize.width()) {
         ASSERT(m_pageDefinedConstraints.layoutSize.width() > 0);
         float adjustedLayoutSizeHeight = (adjustedLayoutSizeWidth * m_pageDefinedConstraints.layoutSize.height()) / m_pageDefinedConstraints.layoutSize.width();
         m_pageDefinedConstraints.layoutSize.setWidth(adjustedLayoutSizeWidth);
         m_pageDefinedConstraints.layoutSize.setHeight(adjustedLayoutSizeHeight);
     }
 }
 
 } // namespace WebCore