Adds scroll position/scale emulation to DevTools.

third_party/WebKit/Source/core/inspector/browser_protocol.json

Index: third_party/WebKit/Source/core/inspector/browser_protocol.json
diff --git a/third_party/WebKit/Source/core/inspector/browser_protocol.json b/third_party/WebKit/Source/core/inspector/browser_protocol.json
index e509d84bf315658c53ec1940fa5ec2660625112b..8400c831ac185a6e68c2e229973adeffcba722d4 100644
--- a/third_party/WebKit/Source/core/inspector/browser_protocol.json
+++ b/third_party/WebKit/Source/core/inspector/browser_protocol.json
@@ -748,6 +748,21 @@
                 "handlers": ["browser"]
             },
             {
+                "name": "setScrollAndScaleOverride",
+                "description": "Overrides the scroll position of layout and visual viewport and the visual viewport scale.",
+                "parameters": [
+                    { "name": "scrollPositionX", "type": "integer", "optional": true, "description": "Fix horizontal scroll position of layout viewport to an override value (device-independent pixel)." },
+                    { "name": "scrollPositionY", "type": "integer", "optional": true, "description": "Fix  vertical scroll position of layout viewport to an override value (device-independent pixel)." },
+                    { "name": "visualViewportPositionX", "type": "number", "optional": true, "description": "Fix horizontal scroll position of visual viewport to an override value (partial device-independent pixels, relative to |scrollPositionX|)." },
+                    { "name": "visualViewportPositionY", "type": "number", "optional": true, "description": "Fix vertical scroll position of visual viewport to an override value (partial device-independent pixels, relative to |scrollPositionY|)." },
+                    { "name": "visualViewportScale", "type": "number", "optional": true, "description": "Fix pinch-zoom scale of the visual viewport to an override value (0 < value <= 10.0, 1.0 is default-scale)." }
+                ]
+            },
+            {
+                "name": "clearScrollAndScaleOverride",
+                "description": "Clears any active scroll and scale override."
+            },
+            {
                 "name": "resetPageScaleFactor",
                 "description": "Requests that page scale factor is reset to initial values."
             },