Adds scroll position/scale emulation to DevTools.

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

Index: third_party/WebKit/Source/core/frame/FrameHost.cpp
diff --git a/third_party/WebKit/Source/core/frame/FrameHost.cpp b/third_party/WebKit/Source/core/frame/FrameHost.cpp
index aa29cf0c5b4c71a6bcff71ed060278def6f6a8b7..b6c4c7b6a9c92e7cd9a103e7399ae47e3a02dd3b 100644
--- a/third_party/WebKit/Source/core/frame/FrameHost.cpp
+++ b/third_party/WebKit/Source/core/frame/FrameHost.cpp
@@ -35,6 +35,7 @@
 #include "core/frame/FrameView.h"
 #include "core/frame/PageScaleConstraints.h"
 #include "core/frame/PageScaleConstraintsSet.h"
+#include "core/frame/ScrollAndScaleEmulator.h"
 #include "core/frame/TopControls.h"
 #include "core/frame/VisualViewport.h"
 #include "core/page/Page.h"
@@ -191,6 +192,7 @@ DEFINE_TRACE(FrameHost)
     visitor->trace(m_overscrollController);
     visitor->trace(m_eventHandlerRegistry);
     visitor->trace(m_customElementReactionStack);
+    visitor->trace(m_scrollAndScaleEmulator);
 }
 
 #if ENABLE(ASSERT)
@@ -256,4 +258,25 @@ void FrameHost::setUserAgentPageScaleConstraints(const PageScaleConstraints& new
     rootView->setNeedsLayout();
 }
 
+void FrameHost::setScrollAndScaleOverride(const IntPoint& framePosition, const DoublePoint& visualViewportPosition, float pageScale)
+{
+    if (!page().mainFrame() || !page().mainFrame()->isLocalFrame())
+        return;
+
+    if (!m_scrollAndScaleEmulator)
+        m_scrollAndScaleEmulator = ScrollAndScaleEmulator::create(this);
+
+    m_scrollAndScaleEmulator->update(
+        framePosition, visualViewportPosition, pageScale);
+}
+
+void FrameHost::clearScrollAndScaleOverride()
+{
+    if (!m_scrollAndScaleEmulator)
+        return;
+
+    m_scrollAndScaleEmulator->clear();
+    m_scrollAndScaleEmulator = nullptr;
+}
+
 } // namespace blink