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

ui/views/cocoa/bridged_native_widget.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_VIEWS_COCOA_BRIDGED_NATIVE_WIDGET_H_
 #define UI_VIEWS_COCOA_BRIDGED_NATIVE_WIDGET_H_
 
 #import <Cocoa/Cocoa.h>
 #include <vector>
 
@@ skipping 114 matching lines @@
   // Explicitly set the visibility. This is called when Cocoa requests a draw,
   // but hasn't updated the value of -[NSWindow isVisible] yet.
   void OnVisibilityChangedTo(bool new_visibility);
 
   // Called by the NSWindowDelegate on a scale factor or color space change.
   void OnBackingPropertiesChanged();
 
   // 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

[tapted, 2015/05/22 04:03:12]

nit: start with "Called by the NSWindowDelegate". Maybe this should be some kind
of privateAPI that only the delegate can see... but ObjC doesn't play nice with
`friend` declarations.

[jackhou1, 2015/05/25 04:50:19]

Done.

+  // is processed by NSWindows. Returning true here will cause the event to be
+  // cancelled and reposted at the CGSessionEventTap level. This is used to
+  // determine whether a mouse-down should drag the window.
+  bool ShouldRepostPendingLeftMouseDown(NSPoint location_in_window);
+
   // Called by NativeWidgetMac when the window size constraints change.
   void OnSizeConstraintsChanged();
 
   // See widget.h for documentation.
   InputMethod* CreateInputMethod();
   ui::InputMethod* GetHostInputMethod();
 
   // The restored bounds will be derived from the current NSWindow frame unless
   // fullscreen or transitioning between fullscreen states.
   gfx::Rect GetRestoredBounds() const;
@@ skipping 37 matching lines @@
   void DestroyCompositor();
 
   // Installs the NSView for hosting the composited layer. It is later provided
   // to |compositor_widget_| via AcceleratedWidgetGetNSView().
   void AddCompositorSuperview();
 
   // Size the layer to match the client area bounds, taking into account display
   // scale factor.
   void UpdateLayerProperties();
 
+  // Sets mouseDownCanMoveWindow on |bridged_view_| and triggers the NSWindow to
+  // update its draggable region.
+  void SetDraggable(bool draggable);
+
   // Overridden from CocoaMouseCaptureDelegate:
   void PostCapturedEvent(NSEvent* event) override;
   void OnMouseCaptureLost() override;
 
   // Returns a properties dictionary associated with the NSWindow.
   // Creates and attaches a new instance if not found.
   NSMutableDictionary* GetWindowProperties() const;
 
   // Overridden from FocusChangeListener:
   void OnWillChangeFocus(View* focused_before,
@@ skipping 56 matching lines @@
   // If true, the window is either visible, or wants to be visible but is
   // currently hidden due to having a hidden parent.
   bool wants_to_be_visible_;
 
   DISALLOW_COPY_AND_ASSIGN(BridgedNativeWidget);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_COCOA_BRIDGED_NATIVE_WIDGET_H_