Add Vector2d classes that represent offsets, instead of using Point.

content/renderer/render_view_impl.cc

Index: content/renderer/render_view_impl.cc
diff --git a/content/renderer/render_view_impl.cc b/content/renderer/render_view_impl.cc
index 3d774af1dbb50a135557eb323885581b7faa2aab..6f8a8ba3fbcfab2ec6e2b5779a49588858901e1e 100644
--- a/content/renderer/render_view_impl.cc
+++ b/content/renderer/render_view_impl.cc
@@ -2166,8 +2166,8 @@ void RenderViewImpl::showContextMenu(
                          start_rect.bottom());
   gfx::Point end_point(end_rect.right(),
                        end_rect.bottom());
-  params.selection_start = GetScrollOffset().Add(start_point);
-  params.selection_end = GetScrollOffset().Add(end_point);
+  params.selection_start = start_point.Add(GetScrollOffset());
+  params.selection_end = end_point.Add(GetScrollOffset());
 #endif
 
   Send(new ViewHostMsg_ContextMenu(routing_id_, params));
@@ -2237,9 +2237,10 @@ void RenderViewImpl::startDragging(WebFrame* frame,
                                    const WebDragData& data,
                                    WebDragOperationsMask mask,
                                    const WebImage& image,
-                                   const WebPoint& imageOffset) {
+                                   const WebPoint& webImageOffset) {
   WebDropData drop_data(data);
   drop_data.referrer_policy = frame->document().referrerPolicy();
+  gfx::Vector2d imageOffset(gfx::Point(webImageOffset).OffsetFromOrigin());
   Send(new DragHostMsg_StartDragging(routing_id_,
                                      drop_data,
                                      mask,
@@ -5511,9 +5512,9 @@ webkit::ppapi::PluginInstance* RenderViewImpl::GetBitmapForOptimizedPluginPaint(
       paint_bounds, dib, location, clip, scale_factor);
 }
 
-gfx::Point RenderViewImpl::GetScrollOffset() {
+gfx::Vector2d RenderViewImpl::GetScrollOffset() {
   WebSize scroll_offset = webview()->mainFrame()->scrollOffset();
-  return gfx::Point(scroll_offset.width, scroll_offset.height);
+  return gfx::Vector2d(scroll_offset.width, scroll_offset.height);
 }
 
 void RenderViewImpl::OnClearFocusedNode() {