Adds link disambiguation popup support to Windows.

content/browser/renderer_host/render_widget_host_impl.cc

Index: content/browser/renderer_host/render_widget_host_impl.cc
diff --git a/content/browser/renderer_host/render_widget_host_impl.cc b/content/browser/renderer_host/render_widget_host_impl.cc
index 8ca48bc231fa6c421265c9822173a90db1ea9570..f641c41f2a443ed3061d4e22d0bc229a85e05b83 100644
--- a/content/browser/renderer_host/render_widget_host_impl.cc
+++ b/content/browser/renderer_host/render_widget_host_impl.cc
@@ -1637,13 +1637,17 @@ void RenderWidgetHostImpl::OnShowDisambiguationPopup(
   SkBitmap zoomed_bitmap;
   zoomed_bitmap.installPixels(info, bitmap->pixels(), info.minRowBytes());
 
-#if defined(OS_ANDROID)
+#if defined(OS_ANDROID) || defined(OS_WIN)
+  // Note that |rect| is in coordinates of pixels relative to the window origin.
+  // Aura-based systems will want to convert this to DIPs.
   if (view_)
     view_->ShowDisambiguationPopup(rect, zoomed_bitmap);
 #else
   NOTIMPLEMENTED();
 #endif
 
+  // It is assumed that the disambiguation popup will make a copy of the
+  // provided zoomed image, so we delete this one.
   zoomed_bitmap.setPixels(0);
   Send(new ViewMsg_ReleaseDisambiguationPopupBitmap(GetRoutingID(), id));
 }