Adds scroll position/scale emulation to DevTools.

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

Index: third_party/WebKit/Source/core/frame/FrameView.cpp
diff --git a/third_party/WebKit/Source/core/frame/FrameView.cpp b/third_party/WebKit/Source/core/frame/FrameView.cpp
index 92177225f6e30dbaa865f5197f386664f36000e4..1b6ba285fb911d97e3fff801e60540c97f02f8b1 100644
--- a/third_party/WebKit/Source/core/frame/FrameView.cpp
+++ b/third_party/WebKit/Source/core/frame/FrameView.cpp
@@ -43,6 +43,7 @@
 #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"
@@ -1586,6 +1587,12 @@ void FrameView::setScrollPosition(const DoublePoint& scrollPoint, ScrollType scr
     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();
@@ -3168,6 +3175,10 @@ IntPoint FrameView::maximumScrollPosition() const
     IntSize visibleSize = visibleContentSize(ExcludeScrollbars) + topControlsSize();
     IntSize contentBounds = contentsSize();
     IntPoint maximumPosition = -scrollOrigin() + (contentBounds - visibleSize);
+
+    if (m_scrollAndScaleEmulator)
+        maximumPosition = m_scrollAndScaleEmulator->applyFramePositionOverride(maximumPosition);
+
     return maximumPosition.expandedTo(minimumScrollPosition());
 }
 
@@ -3287,7 +3298,12 @@ IntSize FrameView::contentsSize() const
 
 IntPoint FrameView::minimumScrollPosition() const
 {
-    return IntPoint(-scrollOrigin().x(), -scrollOrigin().y());
+    IntPoint minimumPosition(-scrollOrigin().x(), -scrollOrigin().y());
+
+    if (m_scrollAndScaleEmulator)
+        minimumPosition = m_scrollAndScaleEmulator->applyFramePositionOverride(minimumPosition);
+
+    return minimumPosition;
 }
 
 void FrameView::adjustScrollbarOpacity()