Adds scroll position/scale emulation to DevTools.

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

Index: third_party/WebKit/Source/core/frame/FrameHost.h
diff --git a/third_party/WebKit/Source/core/frame/FrameHost.h b/third_party/WebKit/Source/core/frame/FrameHost.h
index 1a44fcc848d8208c7fd58c90928f9908e20799fb..e1433a1a7a71376cc78e0b9b1a7c1fe5b611e912 100644
--- a/third_party/WebKit/Source/core/frame/FrameHost.h
+++ b/third_party/WebKit/Source/core/frame/FrameHost.h
@@ -44,11 +44,14 @@ class ChromeClient;
 class ConsoleMessageStorage;
 class CustomElementReactionStack;
 class Deprecation;
+class DoublePoint;
 class EventHandlerRegistry;
+class IntPoint;
 class OverscrollController;
 class Page;
 struct PageScaleConstraints;
 class PageScaleConstraintsSet;
+class ScrollAndScaleEmulator;
 class Settings;
 class TopControls;
 class UseCounter;
@@ -134,6 +137,11 @@ public:
     void setDefaultPageScaleLimits(float minScale, float maxScale);
     void setUserAgentPageScaleConstraints(const PageScaleConstraints& newConstraints);
 
+    // Override the page scale and scroll positions of main frame and visual viewport.
+    void setScrollAndScaleOverride(const IntPoint& framePosition, const DoublePoint& visualViewportPosition, float pageScale);
+    void clearScrollAndScaleOverride();
+    ScrollAndScaleEmulator* scrollAndScaleEmulator() { return m_scrollAndScaleEmulator; }
+
 private:
     explicit FrameHost(Page&);
 
@@ -145,6 +153,7 @@ private:
     const Member<EventHandlerRegistry> m_eventHandlerRegistry;
     const Member<ConsoleMessageStorage> m_consoleMessageStorage;
     const Member<CustomElementReactionStack> m_customElementReactionStack;
+    Member<ScrollAndScaleEmulator> m_scrollAndScaleEmulator;
 
     AtomicString m_overrideEncoding;
     int m_subframeCount;