Adds scroll position/scale emulation to DevTools.

third_party/WebKit/Source/web/WebViewImpl.h

Index: third_party/WebKit/Source/web/WebViewImpl.h
diff --git a/third_party/WebKit/Source/web/WebViewImpl.h b/third_party/WebKit/Source/web/WebViewImpl.h
index af2b14985a8f9cb3a489a53b8682e734f72b6692..d88f9a68593caccf06b9e2266c7213bd683ccff2 100644
--- a/third_party/WebKit/Source/web/WebViewImpl.h
+++ b/third_party/WebKit/Source/web/WebViewImpl.h
@@ -69,6 +69,7 @@
 
 namespace blink {
 
+class CompositorMutatorImpl;
 class DataObject;
 class DevToolsEmulator;
 class Frame;
@@ -87,7 +88,6 @@ class WebLayerTreeView;
 class WebLocalFrame;
 class WebLocalFrameImpl;
 class WebImage;
-class CompositorMutatorImpl;
 class WebPagePopupImpl;
 class WebPlugin;
 class WebRemoteFrame;
@@ -527,6 +527,10 @@ private:
     void setPageScaleFactorAndLocation(float, const FloatPoint&);
     void propagateZoomFactorToLocalFrameRoots(Frame*, float);
 
+    // Override the page scale and scroll positions of main frame and visual viewport.
+    void setScrollAndScaleOverride(const WebDeviceEmulationParams&);
+    void clearScrollAndScaleOverride();
+
     void scrollAndRescaleViewports(float scaleFactor, const IntPoint& mainFrameOrigin, const FloatPoint& visualViewportOrigin);
 
     float maximumLegiblePageScale() const;