Adds scroll position/scale emulation to DevTools.

third_party/WebKit/Source/core/frame/FrameView.cpp

 /*
  * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
  *                     1999 Lars Knoll <knoll@kde.org>
  *                     1999 Antti Koivisto <koivisto@kde.org>
  *                     2000 Dirk Mueller <mueller@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  *           (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
@@ skipping 26 matching lines @@
 #include "core/editing/EditingUtilities.h"
 #include "core/editing/FrameSelection.h"
 #include "core/editing/RenderedPosition.h"
 #include "core/editing/markers/DocumentMarkerController.h"
 #include "core/fetch/ResourceFetcher.h"
 #include "core/frame/EventHandlerRegistry.h"
 #include "core/frame/FrameHost.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Location.h"
 #include "core/frame/PageScaleConstraintsSet.h"
+#include "core/frame/ScrollAndScaleEmulator.h"
 #include "core/frame/Settings.h"
 #include "core/frame/TopControls.h"
 #include "core/frame/VisualViewport.h"
 #include "core/html/HTMLFrameElement.h"
 #include "core/html/HTMLPlugInElement.h"
 #include "core/html/HTMLTextFormControlElement.h"
 #include "core/html/parser/TextResourceDecoder.h"
 #include "core/input/EventHandler.h"
 #include "core/inspector/InspectorInstrumentation.h"
 #include "core/inspector/InspectorTraceEvents.h"
@@ skipping 1539 matching lines @@
     DoublePoint newScrollPosition = clampScrollPosition(scrollPoint);
     if (newScrollPosition == scrollPositionDouble())
         return;
 
     if (scrollBehavior == ScrollBehaviorAuto)
         scrollBehavior = scrollBehaviorStyle();
 
     ScrollableArea::setScrollPosition(newScrollPosition, scrollType, scrollBehavior);
 }
 
+void FrameView::setScrollAndScaleEmulator(const RefPtr<ScrollAndScaleEmulator>& emulator)
+{
+    m_scrollAndScaleEmulator = emulator;
+    setScrollPosition(scrollPosition(), ProgrammaticScroll, ScrollBehaviorInstant);
+}
+
 void FrameView::didUpdateElasticOverscroll()
 {
     Page* page = frame().page();
     if (!page)
         return;
     FloatSize elasticOverscroll = page->chromeClient().elasticOverscroll();
     if (m_horizontalScrollbar) {
         float delta = elasticOverscroll.width() - m_horizontalScrollbar->elasticOverscroll();
         if (delta != 0) {
             m_horizontalScrollbar->setElasticOverscroll(elasticOverscroll.width());
@@ skipping 1549 matching lines @@
     ScrollableArea::didAddScrollbar(scrollbar, orientation);
 }
 
 void FrameView::setTopControlsViewportAdjustment(float adjustment)
 {
     m_topControlsViewportAdjustment = adjustment;
 }
 
 IntPoint FrameView::maximumScrollPosition() const
 {
+    IntPoint minimum = calculateMinimumScrollPosition();
+    IntPoint maximum = calculateMaximumScrollPosition().expandedTo(minimum);
+
+    if (m_scrollAndScaleEmulator) {

[bokan, 2016/07/01 21:05:12]

Nit: no braces

[Eric Seckler, 2016/07/04 14:33:08]

Done.

+        return m_scrollAndScaleEmulator->applyFramePositionOverride(maximum, minimum, maximum);

[bokan, 2016/07/01 21:05:12]

I would remove the min and max parameters from applyFramePositionOverride and
clamp it to the physical limits after the override call.

[Eric Seckler, 2016/07/04 14:33:08]

Done.

+    }
+
+    return maximum;
+}
+
+IntPoint FrameView::calculateMaximumScrollPosition() const
+{
     // Make the same calculation as in CC's LayerImpl::MaxScrollOffset()
     // FIXME: We probably shouldn't be storing the bounds in a float. crbug.com/422331.
     IntSize visibleSize = visibleContentSize(ExcludeScrollbars) + topControlsSize();
     IntSize contentBounds = contentsSize();
     IntPoint maximumPosition = -scrollOrigin() + (contentBounds - visibleSize);
-    return maximumPosition.expandedTo(minimumScrollPosition());
+    return maximumPosition;
 }
 
 void FrameView::addChild(Widget* child)
 {
     ASSERT(child != this && !child->parent());
     child->setParent(this);
     m_children.add(child);
 }
 
 void FrameView::setHasHorizontalScrollbar(bool hasBar)
@@ skipping 98 matching lines @@
     return IntRect(flooredIntPoint(m_scrollPosition), visibleContentSize(scrollbarInclusion));
 }
 
 IntSize FrameView::contentsSize() const
 {
     return m_contentsSize;
 }
 
 IntPoint FrameView::minimumScrollPosition() const
 {
+    if (m_scrollAndScaleEmulator) {
+        IntPoint minimum = calculateMinimumScrollPosition();
+        IntPoint maximum = calculateMaximumScrollPosition().expandedTo(minimum);
+        return m_scrollAndScaleEmulator->applyFramePositionOverride(minimum, minimum, maximum);
+    }
+
+    return calculateMinimumScrollPosition();
+}
+
+IntPoint FrameView::calculateMinimumScrollPosition() const
+{
     return IntPoint(-scrollOrigin().x(), -scrollOrigin().y());
 }
 
 void FrameView::adjustScrollbarOpacity()
 {
     if (m_horizontalScrollbar && layerForHorizontalScrollbar()) {
         bool isOpaqueScrollbar = !m_horizontalScrollbar->isOverlayScrollbar();
         layerForHorizontalScrollbar()->setContentsOpaque(isOpaqueScrollbar);
     }
     if (m_verticalScrollbar && layerForVerticalScrollbar()) {
@@ skipping 930 matching lines @@
     return m_subtreeThrottled || (m_hiddenForThrottling && m_crossOriginForThrottling);
 }
 
 LayoutBox& FrameView::boxForScrollControlPaintInvalidation() const
 {
     ASSERT(!layoutViewItem().isNull());
     return *layoutView();
 }
 
 } // namespace blink