Adds DevTools commands for forced viewport override.

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

 {
     "version": { "major": "1", "minor": "1" },
     "domains": [{
         "domain": "Inspector",
         "experimental": true,
         "types": [],
         "commands": [
             {
                 "name": "enable",
                 "description": "Enables inspector domain notifications.",
@@ skipping 712 matching lines @@
         "commands": [
             {
                 "name": "setDeviceMetricsOverride",
                 "description": "Overrides the values of device screen dimensions (window.screen.width, window.screen.height, window.innerWidth, window.innerHeight, and \"device-width\"/\"device-height\"-related CSS media query results).",
                 "parameters": [
                     { "name": "width", "type": "integer", "description": "Overriding width value in pixels (minimum 0, maximum 10000000). 0 disables the override." },
                     { "name": "height", "type": "integer", "description": "Overriding height value in pixels (minimum 0, maximum 10000000). 0 disables the override." },
                     { "name": "deviceScaleFactor", "type": "number", "description": "Overriding device scale factor value. 0 disables the override." },
                     { "name": "mobile", "type": "boolean", "description": "Whether to emulate mobile device. This includes viewport meta tag, overlay scrollbars, text autosizing and more." },
                     { "name": "fitWindow", "type": "boolean", "description": "Whether a view that exceeds the available browser window area should be scaled down to fit." },
-                    { "name": "scale", "type": "number", "optional": true, "description": "Scale to apply to resulting view image. Ignored in |fitWindow| mode." },
-                    { "name": "offsetX", "type": "number", "optional": true, "description": "X offset to shift resulting view image by. Ignored in |fitWindow| mode." },
-                    { "name": "offsetY", "type": "number", "optional": true, "description": "Y offset to shift resulting view image by. Ignored in |fitWindow| mode." },
+                    { "name": "scale", "type": "number", "optional": true, "deprecated": true, "description": "Not used." },

[dgozman, 2016/08/22 22:22:06]

Please leave the scale, it's used by DevTools.

[Eric Seckler, 2016/08/23 09:32:19]

Ah, misunderstood you. Is it missing tests? (I didn't see anything under
inspector/ or inspector-protocol/ breaking.)

+                    { "name": "offsetX", "type": "number", "optional": true, "deprecated": true, "description": "Not used." },
+                    { "name": "offsetY", "type": "number", "optional": true, "deprecated": true, "description": "Not used." },
                     { "name": "screenWidth", "type": "integer", "optional": true, "description": "Overriding screen width value in pixels (minimum 0, maximum 10000000). Only used for |mobile==true|." },
                     { "name": "screenHeight", "type": "integer", "optional": true, "description": "Overriding screen height value in pixels (minimum 0, maximum 10000000). Only used for |mobile==true|." },
                     { "name": "positionX", "type": "integer", "optional": true, "description": "Overriding view X position on screen in pixels (minimum 0, maximum 10000000). Only used for |mobile==true|." },
                     { "name": "positionY", "type": "integer", "optional": true, "description": "Overriding view Y position on screen in pixels (minimum 0, maximum 10000000). Only used for |mobile==true|." },
                     { "name": "screenOrientation", "$ref": "ScreenOrientation", "optional": true, "description": "Screen orientation override." }
                 ],
                 "handlers": ["browser"]
             },
             {
                 "name": "clearDeviceMetricsOverride",
                 "description": "Clears the overriden device metrics.",
                 "handlers": ["browser"]
             },
             {
+                "name": "forceViewport",
+                "description": "Overrides the visible area of the page. The change is hidden from the page, i.e. the observable scroll position and page scale does not change. In effect, the command moves the specified area of the page into the top-left corner of the frame.",
+                "parameters": [
+                    { "name": "x", "type": "number", "description": "X coordinate of top-left corner of the area (CSS pixels)." },
+                    { "name": "y", "type": "number", "description": "Y coordinate of top-left corner of the area (CSS pixels)." },
+                    { "name": "scale", "type": "number", "optional": true, "description": "Scale to apply to the area (relative to a page scale of 1.0). Defaults to 1.0." }

[chrishtr, 2016/08/22 22:00:42]

What is the origin of this scale?

[Eric Seckler, 2016/08/23 09:32:19]

It's relative to a page scale of 1.0 and effectively overrides the page scale.
We'll be using this to e.g. create thumbnail screenshots (or e.g. "zoomed"
screenshots of elements on a page). The reason we're supplying it here rather
than setting it with via setPageScaleFactor is that changes to the page scale
factor are visible to the page (e.g. through window.innerWidth/Height), so we're
instead adapting to changes in the page scale.

+                ]
+            },
+            {
+                "name": "resetViewport",
+                "description": "Resets the visible area of the page to the original viewport, undoing any effects of the forceViewport command."
+            },
+            {
                 "name": "resetPageScaleFactor",
                 "description": "Requests that page scale factor is reset to initial values."
             },
             {
                 "name": "setPageScaleFactor",
                 "description": "Sets a specified page scale factor.",
                 "parameters": [
                     { "name": "pageScaleFactor", "type": "number", "description": "Page scale factor." }
                 ]
             },
@@ skipping 3723 matching lines @@
                 "description": "Informs that port was successfully bound and got a specified connection id.",
                 "parameters": [
                     {"name": "port", "type": "integer", "description": "Port number that was successfully bound." },
                     {"name": "connectionId", "type": "string", "description": "Connection id to be used." }
                 ],
                 "handlers": ["browser"]
             }
         ]
     }]
 }