[MacViews] Enable dragging a window by its caption/draggable areas.

ui/views/cocoa/bridged_native_widget.h

Index: ui/views/cocoa/bridged_native_widget.h
diff --git a/ui/views/cocoa/bridged_native_widget.h b/ui/views/cocoa/bridged_native_widget.h
index badda952339963177b0c5ded3ec992bb78f4d53e..7eb8fbcd3abc56d484e86123b0705af9ff32ff85 100644
--- a/ui/views/cocoa/bridged_native_widget.h
+++ b/ui/views/cocoa/bridged_native_widget.h
@@ -29,6 +29,7 @@ class InputMethod;
 namespace views {
 
 class CocoaMouseCapture;
+class CocoaNonClientDrag;
 class InputMethod;
 class NativeWidgetMac;
 class View;
@@ -132,6 +133,11 @@ class VIEWS_EXPORT BridgedNativeWidget : public ui::LayerDelegate,
   // Called by the NSWindowDelegate when the window becomes or resigns key.
   void OnWindowKeyStatusChangedTo(bool is_key);
 
+  // Called when the application receives a mouse-down, but before the event
+  // is processed by NSWindows. Returning true here will cause the event to be
+  // reposted.

[tapted, 2015/05/20 07:18:15]

Perhaps say why this exists here.

[jackhou1, 2015/05/22 02:49:16]

Done.

+  bool OnWindowWillReceiveLeftMouseDown(NSPoint location_in_window);

[tapted, 2015/05/20 07:18:15]

perhaps ShouldRepostPendingLeftMouseDown ?

[jackhou1, 2015/05/22 02:49:16]

Done.

+
   // Called by NativeWidgetMac when the window size constraints change.
   void OnSizeConstraintsChanged();
 
@@ -228,6 +234,7 @@ class VIEWS_EXPORT BridgedNativeWidget : public ui::LayerDelegate,
   base::scoped_nsobject<BridgedContentView> bridged_view_;
   scoped_ptr<ui::InputMethod> input_method_;
   scoped_ptr<CocoaMouseCapture> mouse_capture_;
+  scoped_ptr<CocoaNonClientDrag> non_client_drag_;
   FocusManager* focus_manager_;  // Weak. Owned by our Widget.
   Widget::InitParams::Type widget_type_;