Add Get/SetDisplayLayout to chrome.system.display extension API

extensions/common/api/system_display.idl

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Use the <code>system.display</code> API to query display metadata.
 namespace system.display {
 
   dictionary Bounds {
     // The x-coordinate of the upper-left corner.
     long left;
@@ skipping 41 matching lines @@
     // The display mode device scale factor.
     double deviceScaleFactor;
 
     // True if the mode is the display's native mode.
     boolean isNative;
 
     // True if the display mode is currently selected.
     boolean isSelected;
   };
 
+  // Layout position, i.e. edge of parent that the display is attached to.
+  enum LayoutPosition { top, right, bottom, left };
+
+  dictionary DisplayLayout {
+    // The unique identifier of the display.
+    DOMString id;
+
+    // The unique identifier of the parent display. Empty if this is the root.
+    DOMString parentId;
+
+    // The layout position of this display relative to the parent. This will
+    // be ignored for the root.
+    LayoutPosition position;
+
+    // The offset of the display along the connected edge. 0 indicates that
+    // the topmost or leftmost corners are aligned.
+    long offset;
+  };
+
   dictionary DisplayUnitInfo {
     // The unique identifier of the display.
     DOMString id;
 
     // The user-friendly name (e.g. "HP LCD monitor").
     DOMString name;
 
     // Chrome OS only. Identifier of the display that is being mirrored if
     // mirroring is enabled, otherwise empty. This will be set for all displays
     // (including the display being mirrored).
@@ skipping 73 matching lines @@
 
     // If set, updates the display's logical bounds origin along y-axis.
     // See documentation for <code>boundsOriginX</code> parameter.
     long? boundsOriginY;
 
     // If set, updates the display mode to the mode matching this value.
     DisplayMode? displayMode;
   };
 
   callback DisplayInfoCallback = void (DisplayUnitInfo[] displayInfo);
+  callback DisplayLayoutCallback = void (DisplayLayout[] layouts);
   callback SetDisplayUnitInfoCallback = void();
+  callback SetDisplayLayoutCallback = void();
 
   interface Functions {
     // Get the information of all attached display devices.
     static void getInfo(DisplayInfoCallback callback);
 
+    // Get the layout info for all displays.
+    // NOTE: This is only available to Chrome OS Kiosk apps and Web UI.
+    static void getDisplayLayout(DisplayLayoutCallback callback);
+
     // Updates the properties for the display specified by |id|, according to
     // the information provided in |info|. On failure, $(ref:runtime.lastError)
     // will be set.
     // NOTE: This is only available to Chrome OS Kiosk apps and Web UI.
     // |id|: The display's unique identifier.
     // |info|: The information about display properties that should be changed.
     //     A property will be changed only if a new value for it is specified in
     //     |info|.
     // |callback|: Empty function called when the function finishes. To find out
     //     whether the function succeeded, $(ref:runtime.lastError) should be
     //     queried.
     static void setDisplayProperties(
         DOMString id,
         DisplayProperties info,
         optional SetDisplayUnitInfoCallback callback);
 
+    // Set the layout for all displays. Any display not included will use the
+    // default layout. If a layout would overlap or be otherwise invalid it
+    // will be adjusted to a valid layout. After layout is resolved, an
+    // onDisplayChanged event will be triggered.
+    // NOTE: This is only available to Chrome OS Kiosk apps and Web UI.
+    // |layouts|: The layout information, required for all displays except
+    //     the primary display.
+    // |callback|: Empty function called when the function finishes. To find out
+    //     whether the function succeeded, $(ref:runtime.lastError) should be
+    //     queried.
+    static void setDisplayLayout(DisplayLayout[] layouts,
+                                 optional SetDisplayLayoutCallback callback);
+
     // Enables/disables the unified desktop feature. Note that this simply
     // enables the feature, but will not change the actual desktop mode.
     // (That is, if the desktop is in mirror mode, it will stay in mirror mode)
     // NOTE: This is only available to Chrome OS Kiosk apps and Web UI.
     // |enabled|: True if unified desktop should be enabled.
     static void enableUnifiedDesktop(boolean enabled);
 
     // Starts overscan calibration for a display. This will show an overlay
     // on the screen indicating the current overscan insets. If overscan
     // calibration for display |id| is in progress this will reset calibration.
@@ skipping 17 matching lines @@
     // and hiding the overlay.
     // |id|: The display's unique identifier.
     static void overscanCalibrationComplete(DOMString id);
   };
 
   interface Events {
     // Fired when anything changes to the display configuration.
     static void onDisplayChanged();
   };
 };