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

chrome/browser/ui/views/tabs/tab_drag_controller.cc

Index: chrome/browser/ui/views/tabs/tab_drag_controller.cc
diff --git a/chrome/browser/ui/views/tabs/tab_drag_controller.cc b/chrome/browser/ui/views/tabs/tab_drag_controller.cc
index 7fff1e9c3df45449a880f33580f733ee1c381380..a3fc6143189524c3e4cb1d4451dde5fae3da5b25 100644
--- a/chrome/browser/ui/views/tabs/tab_drag_controller.cc
+++ b/chrome/browser/ui/views/tabs/tab_drag_controller.cc
@@ -112,7 +112,7 @@ class DockView : public views::View {
     bool rtl_ui = base::i18n::IsRTL();
     if (rtl_ui) {
       // Flip canvas to draw the mirrored tab images for RTL UI.
-      canvas->Translate(gfx::Point(width(), 0));
+      canvas->Translate(gfx::Vector2d(width(), 0));
       canvas->Scale(-1, 1);
     }
     int x_of_active_tab = width() / 2 + kTabSpacing / 2;
@@ -502,8 +502,8 @@ void TabDragController::Drag(const gfx::Point& point_in_screen) {
     Attach(source_tabstrip_, gfx::Point());
     if (detach_into_browser_ && static_cast<int>(drag_data_.size()) ==
         GetModel(source_tabstrip_)->count()) {
-      gfx::Point dragged_view_point = GetWindowOffset(point_in_screen);
-      RunMoveLoop(dragged_view_point);
+      gfx::Vector2d dragged_view_offset = GetWindowOffset(point_in_screen);

[Peter Kasting, 2012/10/30 01:14:14]

Nit: Inline

+      RunMoveLoop(dragged_view_offset);
       return;
     }
   }
@@ -1297,8 +1297,8 @@ void TabDragController::DetachIntoNewBrowserAndRunMoveLoop(
     // All the tabs in a browser are being dragged but all the tabs weren't
     // initially being dragged. For this to happen the user would have to
     // start dragging a set of tabs, the other tabs close, then detach.
-    gfx::Point dragged_view_point = GetWindowOffset(point_in_screen);
-    RunMoveLoop(dragged_view_point);
+    gfx::Vector2d dragged_view_offset = GetWindowOffset(point_in_screen);

[Peter Kasting, 2012/10/30 01:14:14]

Nit: Inline

+    RunMoveLoop(dragged_view_offset);
     return;
   }
 
@@ -1312,7 +1312,7 @@ void TabDragController::DetachIntoNewBrowserAndRunMoveLoop(
   std::vector<gfx::Rect> drag_bounds =
       CalculateBoundsForDraggedTabs(attached_point.x());
 
-  gfx::Point drag_offset;
+  gfx::Vector2d drag_offset;
   Browser* browser = CreateBrowserForDrag(
       attached_tabstrip_, point_in_screen, &drag_offset, &drag_bounds);
   Detach(DONT_RELEASE_CAPTURE);
@@ -1335,7 +1335,7 @@ void TabDragController::DetachIntoNewBrowserAndRunMoveLoop(
   RunMoveLoop(drag_offset);
 }
 
-void TabDragController::RunMoveLoop(const gfx::Point& drag_offset) {
+void TabDragController::RunMoveLoop(const gfx::Vector2d& drag_offset) {
   // If the user drags the whole window we'll assume they are going to attach to
   // another window and therefor want to reorder.
   move_behavior_ = REORDER;
@@ -1969,7 +1969,7 @@ bool TabDragController::AreTabsConsecutive() {
 Browser* TabDragController::CreateBrowserForDrag(
     TabStrip* source,
     const gfx::Point& point_in_screen,
-    gfx::Point* drag_offset,
+    gfx::Vector2d* drag_offset,
     std::vector<gfx::Rect>* drag_bounds) {
   gfx::Point center(0, source->height() / 2);
   views::View::ConvertPointToWidget(source, &center);
@@ -1996,7 +1996,7 @@ Browser* TabDragController::CreateBrowserForDrag(
       break; // Nothing to do for DETACH_ABOVE_OR_BELOW.
   }
 
-  *drag_offset = point_in_screen.Subtract(new_bounds.origin());
+  *drag_offset = point_in_screen - new_bounds.origin();
 
   Browser::CreateParams create_params(drag_data_[0].contents->profile());
   create_params.initial_bounds = new_bounds;
@@ -2027,13 +2027,13 @@ gfx::Point TabDragController::GetCursorScreenPoint() {
   return screen_->GetCursorScreenPoint();
 }
 
-gfx::Point TabDragController::GetWindowOffset(
+gfx::Vector2d TabDragController::GetWindowOffset(
     const gfx::Point& point_in_screen) {
   TabStrip* owning_tabstrip = (attached_tabstrip_ && detach_into_browser_) ?
       attached_tabstrip_ : source_tabstrip_;
   views::View* toplevel_view = owning_tabstrip->GetWidget()->GetContentsView();
 
-  gfx::Point offset = point_in_screen;
-  views::View::ConvertPointFromScreen(toplevel_view, &offset);
-  return offset;
+  gfx::Point point = point_in_screen;
+  views::View::ConvertPointFromScreen(toplevel_view, &point);
+  return point.OffsetFromOrigin();

[Peter Kasting, 2012/10/30 01:14:14]

I wonder if view.h should change from having all the current
ConvertPoint{From,To}XXX() functions to simply having some kind of
GetOffsetInScreen() function.  Then code like this would just be "return
point_in_screen - toplevel_view->GetOffsetInScreen();".  And most other places
we convert could be changed similarly.

We might need to have a GetOffsetFromWidget() function too. 
(GetOffsetFromParent() wouldn't be necessary because that's just
bounds().OffsetFromOrigin().)

If this makes sense it would probably be better as a separate change.

[danakj, 2012/10/30 19:21:21]

That sounds pretty reasonable, and like it would reduce a bunch of API.

[Peter Kasting, 2012/10/30 20:24:37]

Should there be a bug for this, then, or are you keeping a list of the specific
API changes we want to follow up with?  (Seems like there were more than just
this, weren't there?)

[danakj, 2012/10/30 21:14:52]

Ya, /me makes bug.

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