Add setSelection function to automation API.

chrome/common/extensions/api/automation.idl

Index: chrome/common/extensions/api/automation.idl
diff --git a/chrome/common/extensions/api/automation.idl b/chrome/common/extensions/api/automation.idl
index b49c3a5e179c58bd70ee76efc89f179bfb0eda68..061bbb4230b2e22646157cbb19950d73667e6179 100644
--- a/chrome/common/extensions/api/automation.idl
+++ b/chrome/common/extensions/api/automation.idl
@@ -312,7 +312,7 @@
     // The root node of the tree containing this AutomationNode.
     AutomationNode root;
 
-    // Whether this AutomationNode is root node.
+    // Whether this AutomationNode is a root node.
     boolean isRootNode;
 
     // The role of this node.
@@ -422,6 +422,19 @@
     DOMString textInputType;
 
     //
+    // Tree selection attributes (available on root nodes only)
+    //
+
+    // The anchor node of the tree selection, if any.
+    AutomationNode? anchorObject;
+    // The anchor offset of the tree selection, if any.
+    long? anchorOffset;
+    // The focus node of the tree selection, if any.
+    AutomationNode? focusObject;
+    // The focus offset of the tree selection, if any.
+    long? focusOffset;
+
+    //
     // Range attributes.
     //
 
@@ -553,5 +566,19 @@
     // Remove a tree change observer.
     [nocompile] static void removeTreeChangeObserver(
         TreeChangeObserver observer);
+
+    // Sets the selection in a tree. This creates a selection in a single
+    // tree (anchorObject and focusObject must have the same root).
+    // Everything in the tree between the two node/offset pairs gets included
+    // in the selection. The anchor is where the user started the selection,
+    // while the focus is the point at which the selection gets extended
+    // e.g. when dragging with a mouse or using the keyboard.  For nodes with
+    // the role staticText, the offset gives the character offset within
+    // the value where the selection starts or ends, respectively.
+    [nocompile] static void setDocumentSelection(
+        [instanceOf=AutomationNode] object anchorObject,
+        long anchorOffset,
+        [instanceOf=AutomationNode] object focusObject,
+        long focusOffset);

[not at google - send to devlin, 2015/10/05 12:56:02]

I'd make this an object with properties "anchorObject", "anchorOffset",
"focusObject", and "focusOffset". I.e. you'd call the function like:

chrome.automation.setDocumentSelection({
  anchorObject: ...,
  anchorOffset: ...,
  focusObject: ...,
  focusOffset: ...,
});

It'd more similar to the OO Range object
(https://developer.mozilla.org/en-US/docs/Web/API/Range) in that it has named
properties vs having a long constructor. Also, it's generally easier to read,
and idiomatic for extension APIs.

You could consider lifting the properties you've added to AutomationNode into a
shared data type (like SelectionRange) but personally I would't bother, since
it's simpler the way you have it, and more consistent with AutomationNode.

   };
 };