[DevTools] Switch from DIP to CSS pixels in device mode.

Source/devtools/protocol.json

Index: Source/devtools/protocol.json
diff --git a/Source/devtools/protocol.json b/Source/devtools/protocol.json
index f69f70587dabb48645605aa7dffb18d720f55f95..25fb5839f57e1a46c0a90547a83a11c80859dd64 100644
--- a/Source/devtools/protocol.json
+++ b/Source/devtools/protocol.json
@@ -190,6 +190,19 @@
                 "hidden": true
             },
             {
+                "id": "Viewport",
+                "type": "object",
+                "description": "Visible page viewport",
+                "properties": [
+                    { "name": "scrollX", "type": "number", "description": "X scroll offset in CSS pixels." },
+                    { "name": "scrollY", "type": "number", "description": "Y scroll offset in CSS pixels." },
+                    { "name": "contentsWidth", "type": "number", "description": "Contents width in CSS pixels." },
+                    { "name": "contentsHeight", "type": "number", "description": "Contents height in CSS pixels." },
+                    { "name": "pageScaleFactor", "type": "number", "description": "Page scale factor." }
+                ],
+                "hidden": true
+            },
+            {
                 "id": "ScreencastFrameMetadata",
                 "type": "object",
                 "description": "Screencast frame metadata",
@@ -648,6 +661,14 @@
                 ],
                 "hidden": true,
                 "handlers": ["browser"]
+            },
+            {
+                "name": "viewportChanged",
+                "description": "Fired when a visible page viewport has changed.",
+                "parameters": [
+                    { "name": "viewport", "$ref": "Viewport", "description": "Viewport description." }
+                ],
+                "hidden": true
             }
         ]
     },