Implemented SetSelection for the Web content on Windows.

content/browser/accessibility/browser_accessibility.h

Index: content/browser/accessibility/browser_accessibility.h
diff --git a/content/browser/accessibility/browser_accessibility.h b/content/browser/accessibility/browser_accessibility.h
index 78047df24c1fcc544e089865405d7c1d62cdb592..c6aea9e55a5f05a15da9320d42e88b0acb0904c4 100644
--- a/content/browser/accessibility/browser_accessibility.h
+++ b/content/browser/accessibility/browser_accessibility.h
@@ -15,10 +15,12 @@
 #include "base/strings/string16.h"
 #include "base/strings/string_split.h"
 #include "build/build_config.h"
+#include "content/browser/accessibility/ax_platform_position.h"
 #include "content/common/content_export.h"
 #include "third_party/WebKit/public/web/WebAXEnums.h"
 #include "ui/accessibility/ax_node.h"
 #include "ui/accessibility/ax_node_data.h"
+#include "ui/accessibility/ax_range.h"
 #include "ui/accessibility/ax_text_utils.h"
 
 // Set PLATFORM_HAS_NATIVE_ACCESSIBILITY_IMPL if this platform has
@@ -357,8 +359,16 @@ class CONTENT_EXPORT BrowserAccessibility {
   std::vector<int> GetLineStartOffsets() const;
 
  protected:
+  using AXPlatformPositionInstance = AXPlatformPosition::AXPositionInstance;
+  using AXPlatformRange = ui::AXRange<AXPlatformPositionInstance::element_type>;
+
   BrowserAccessibility();
 
+  // Creates a position rooted at this object.
+  // This is a text position on all platforms except IA2 and ATK, where tree
+  // positions are created for non-text objects representing hypertext offsets.
+  virtual AXPlatformPositionInstance CreatePositionAt(int offset) const;
+
   // The manager of this tree of accessibility objects.
   BrowserAccessibilityManager* manager_;