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 deeeb5ead2dc278ae8e8ace7f2a6ba7de082d15a..73e06e6a5232b0e1b36857ed06ab91357b6b36c1 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;
@@ -467,6 +467,10 @@ public:
     // Exposed for the purpose of overriding device metrics.
     void sendResizeEventAndRepaint();
 
+    // 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();
+
     // Exposed for testing purposes.
     bool hasHorizontalScrollbar();
     bool hasVerticalScrollbar();