MacViews: Fix sending mouse exit event and releasing capture on D&D.

ui/base/cocoa/base_view.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.

[tapted, 2016/09/21 10:07:05]

CL description - can you flesh it out with some of the info you provided.
There's a formula for change list descriptions at -
http://dev.chromium.org/developers/contributing-code#TOC-Writing-change-list-...

E.g. this one should go something like.

Currently, clicks immediately after a drag in a MacViews window are ignored.
This is because initiating
a drag and drop session with -[NSView beginDraggingSessionWithItems:..]
suppresses the mouse events that would result in capture being released. To fix,
explicitly release Widget capture before starting the dragging session.

It's also possible for captured events to be incorrectly suppressed by stale
logic in BaseView that's no longer needed. Remove it.

 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_BASE_COCOA_BASE_VIEW_H_
 #define UI_BASE_COCOA_BASE_VIEW_H_
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/mac/scoped_nsobject.h"
 #include "base/mac/sdk_forward_declarations.h"
 #import "ui/base/cocoa/tracking_area.h"
 #include "ui/base/ui_base_export.h"
 #include "ui/gfx/geometry/rect.h"
 
 // A view that provides common functionality that many views will need:
 // - Automatic registration for mouse-moved events.
 // - Funneling of mouse and key events to two methods
 // - Coordinate conversion utilities
 UI_BASE_EXPORT
 @interface BaseView : NSView {
  @public
   enum EventHandled {
     kEventNotHandled,
     kEventHandled
   };
 
  @private
   ui::ScopedCrTrackingArea trackingArea_;
-  BOOL dragging_;
-  base::scoped_nsobject<NSEvent> pendingExitEvent_;

[tapted, 2016/09/19 00:31:01]

spqchan is right - we can't change BaseView -- too much other stuff relies on
it, and it's unlikely there is good test coverage for the UI interactions.

Can you explain why it's necessary to remove the `pendingExitEvent_` logic in
order to fix the bug?

Then, if pendingExitEvent_ really is useless for any situation involving
BridgedContentView, then it can be disabled via overriding. E.g.

 - Add a method `handleMouseEvent` which switches on [event type] and does the
updates of dragging_ and pendingExitEvent_ all in the one method
 - Change all the BaseView [foo]MouseBar methods to call handleMouseEvent
instead of mouseEvent
 - override handleMouseEvent in BridgedContentView to just call mouseEvent so
the logic is skipped.

[snake, 2016/09/20 15:04:26]

was
I can not repro case on http://crbug.com/33100, because TestCase.swf is not
correctly opened by current flash version.
I did try reproduce this, using other plugin (Chromium PDF plugin and Yandex PDF
plugin).
in
1) Currently In MacViews on any click the MouseUp event are delivered to
BridgedContentView::processCapturedMouseEvent: , not to BaseView::MouseUp:. This
happens, beacause on MouseDown we call native_widget_->SetCapture(); in
views::Widget::OnMouseEvent, and after that all messages are delivered using
other way.

2) When we create new NSWindow while processing MouseDown (menu for example),
the MouseUp is never received.

3) When we start D&D using NSView::beginDraggingSession[with item]: , the
MouseUp event will be processed by system, and we receive only
NSView::performDragOperation: . 
the
so
Should I create separate CL for changes in base_view.* ?

[tapted, 2016/09/21 10:07:05]

So a possible alternative fix may be to generate a synthetic mouseUp event
that's sent once the dragging session ends. That may even be "nicer", if it
gives views::Views a way to tidy up their state. But if that doesn't happen on
Aura, then it's not likely that Views are expecting that. Also it's more
complicated. So let's go with this.
Hm, I guess there's not much left after removing the unnecessary code - let's
leave it.

   NSInteger pressureEventStage_;
 }
 
 // Override these methods (mouseEvent, keyEvent, forceTouchEvent) in a
 // subclass.
 - (void)mouseEvent:(NSEvent *)theEvent;
 
 // keyEvent should return kEventHandled if it handled the event, or
 // kEventNotHandled if it should be forwarded to BaseView's super class.
 - (EventHandled)keyEvent:(NSEvent *)theEvent;
 
 - (void)forceTouchEvent:(NSEvent*)theEvent;
 
 // Useful rect conversions (doing coordinate flipping)
 - (gfx::Rect)flipNSRectToRect:(NSRect)rect;
 - (NSRect)flipRectToNSRect:(gfx::Rect)rect;
 
 @end
 
 // A notification that a view may issue when it receives first responder status.
 // The name is |kViewDidBecomeFirstResponder|, the object is the view, and the
 // NSSelectionDirection is wrapped in an NSNumber under the key
 // |kSelectionDirection|.
 UI_BASE_EXPORT extern NSString* kViewDidBecomeFirstResponder;
 UI_BASE_EXPORT extern NSString* kSelectionDirection;
 
 #endif  // UI_BASE_COCOA_BASE_VIEW_H_