[EXPERIMENT] MacViews: Implement Tab Dragging

ui/base/test/ui_controls_mac.mm

Index: ui/base/test/ui_controls_mac.mm
diff --git a/ui/base/test/ui_controls_mac.mm b/ui/base/test/ui_controls_mac.mm
index b7615b6c2fd78eab1ddbb87a351cf33f47c4efd1..a4bf8470d4f727983e14add950269fa1896cb655 100644
--- a/ui/base/test/ui_controls_mac.mm
+++ b/ui/base/test/ui_controls_mac.mm
@@ -5,14 +5,21 @@
 #include "ui/base/test/ui_controls.h"
 
 #import <Cocoa/Cocoa.h>
+#include <memory>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/callback.h"
+#import "base/mac/foundation_util.h"
+#import "base/mac/scoped_nsobject.h"
+#import "base/mac/scoped_objc_class_swizzler.h"
 #include "base/message_loop/message_loop.h"
+#include "base/thread_task_runner_handle.h"
 #include "ui/base/cocoa/cocoa_base_utils.h"
 #include "ui/events/keycodes/keyboard_code_conversion_mac.h"
 #import "ui/events/test/cocoa_test_event_utils.h"
+#import "ui/gfx/mac/coordinate_conversion.h"
+#include "ui/gfx/screen.h"
 
 // Implementation details: We use [NSApplication sendEvent:] instead
 // of [NSApplication postEvent:atStart:] so that the event gets sent
@@ -48,10 +55,23 @@ using cocoa_test_event_utils::TimeIntervalSinceSystemStartup;
 
 namespace {
 
+// When enabled, all simulated mouse events will be posted to
+// the WindowServer, and the actual mouse will move on the screen.
+bool g_use_cgevents = false;
+
 // Stores the current mouse location on the screen. So that we can use it
 // when firing keyboard and mouse click events.
 NSPoint g_mouse_location = { 0, 0 };
 
+// If enabled overrides results returned by +[NSEvent mouseLocation] and
+// -[NSWindow mouseLocationOutsideOfEventStream]
+NSPoint g_mouse_location_override = {0, 0};
+bool g_mouse_location_override_enabled = false;
+
+// Stores the current pressed mouse buttons. Indexed by
+// ui_controls::MouseButton.
+bool g_mouse_button_down[3] = {false, false, false};
+
 bool g_ui_controls_enabled = false;
 
 // Creates the proper sequence of autoreleased key events for a key down + up.
@@ -122,9 +142,18 @@ void SynthesizeKeyEventsSequence(NSWindow* window,
   }
 }
 
+void RunTaskInTaskRunner(
+    scoped_refptr<base::SingleThreadTaskRunner> task_runner,
+    const base::Closure& task) {
+  task_runner->PostTask(FROM_HERE, task);
+}
+
 // A helper function to watch for the event queue. The specific task will be
 // fired when there is no more event in the queue.
 void EventQueueWatcher(const base::Closure& task) {
+  DCHECK_EQ(dispatch_get_current_queue(), dispatch_get_main_queue())
+      << "It should be run on the UI thread, as otherwise it will always "
+         "report there are no pending events";
   NSEvent* event = [NSApp nextEventMatchingMask:NSAnyEventMask
                                       untilDate:nil
                                          inMode:NSDefaultRunLoopMode
@@ -173,6 +202,188 @@ NSWindow* WindowAtCurrentMouseLocation() {
 
 }  // namespace
 
+// Since CGEvents take some time to reach -[NSApplication sendEvent:] we use
+// this class to wait for the events to start being processed before sending
+// finish notifications.
+class EventMonitor {
+ public:
+  void NotifyWhenEventIsProcessed(NSEvent* event, const base::Closure& task) {
+    if (g_use_cgevents) {
+      CHECK([[NSApplication sharedApplication] isActive])
+          << "If we generate CGEvents and the application is not active, we'll "
+             "deadlock waiting for NSMouseMoved events. Use "
+             "ui_test_utils::BringBrowserWindowToFront() to activate the "
+             "browser window prior to generating CGEvents.";
+    }
+
+    base::AutoLock auto_lock(lock_);
+    tasks_.emplace_back(Task(event, task));
+  }
+
+  void ProcessingEvent(NSEvent* event) {
+    base::AutoLock auto_lock(lock_);
+    auto it = std::find_if(
+        tasks_.begin(), tasks_.end(),
+        [&event](const Task& task) { return task.MatchesEvent(event); });
+    if (it != tasks_.end()) {
+      it->Run();
+      tasks_.erase(it);
+    }
+  }
+
+  static EventMonitor* Instance() {
+    static EventMonitor* monitor = nullptr;
+    if (!monitor) {
+      monitor = new EventMonitor();
+    }
+    return monitor;
+  }
+
+ private:
+  class Task {
+   public:
+    Task(NSEvent* event, const base::Closure& task)
+        : task_runner_(base::ThreadTaskRunnerHandle::Get()),
+          event_([event retain]),
+          finish_closure_(task) {}
+
+    bool MatchesEvent(NSEvent* event) const {
+      // When moving the window using BridgedNativeWidget::RunMoveLoop the
+      // locationInWindow can be a little inconsistent with what we expect.
+      // Seems that only comparing event type is fine.
+      return
+          [event_ type] == [event type] && [event_ subtype] == [event subtype];
+    }
+
+    void Run() {
+      // We get here before the event is actually processed. Run the
+      // EventQueueWatcher on the main thread in order to wait for all events to
+      // finish processing.
+      base::MessageLoop::current()->PostTask(
+          FROM_HERE, base::Bind(&EventQueueWatcher,
+                                base::Bind(&RunTaskInTaskRunner, task_runner_,
+                                           finish_closure_)));
+    }
+
+   private:
+    // Events could be spawned on background threads. Be sure to invoke the
+    // |finish_closure_| on an appropriate thread.
+    scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
+    base::scoped_nsobject<NSEvent> event_;
+    base::Closure finish_closure_;
+  };
+
+  EventMonitor()
+      : send_event_swizzler_(
+            new base::mac::ScopedObjCClassSwizzler([NSApplication class],
+                                                   @selector(sendEvent:),
+                                                   @selector(cr_sendEvent:))) {}
+
+  std::vector<Task> tasks_;
+
+  // synchronizes access to the |tasks_| in case we spawn the events on a
+  // different thread
+  base::Lock lock_;
+
+  std::unique_ptr<base::mac::ScopedObjCClassSwizzler> send_event_swizzler_;
+
+  DISALLOW_COPY_AND_ASSIGN(EventMonitor);
+};
+
+// Donates testing implementations of NSApplication methods. We can't simply
+// use -[NSEvent addLocalMonitorForEventsMatchingMask:handler:], as other event
+// monitors could have precedence, and they could filter the events before we
+// can see them. But since nobody swizzles -[NSApplication sendEvent:] we should
+// be safe.
+@interface NSApplication (TestingDonor)
+@end
+
+@implementation NSApplication (TestingDonor)
+- (void)cr_sendEvent:(NSEvent*)event {
+  // Invoke the finish handler before the event is processed, since we can get
+  // stuck in BridgedNativeWidget::RunMoveLoop and would never see the event
+  // otherwise.
+  EventMonitor::Instance()->ProcessingEvent(event);
+
+  [self cr_sendEvent:event];
+}
+@end
+
+// Donates testing implementations of NSEvent methods.
+@interface FakeNSEventTestingDonor : NSObject
+@end
+
+@implementation FakeNSEventTestingDonor
++ (NSPoint)mouseLocation {
+  if (g_mouse_location_override_enabled)
+    return g_mouse_location_override;
+
+  return g_mouse_location;
+}
+
++ (NSUInteger)pressedMouseButtons {
+  NSUInteger result = 0;
+  const int buttons[3] = {ui_controls::LEFT, ui_controls::RIGHT,
+                          ui_controls::MIDDLE};
+  for (unsigned int i = 0; i < arraysize(buttons); ++i) {
+    if (g_mouse_button_down[buttons[i]])
+      result |= (1 << i);
+  }
+  return result;
+}
+@end
+
+// Donates testing implementations of NSWindow methods.
+@interface FakeNSWindowTestingDonor : NSObject
+@end
+
+@implementation FakeNSWindowTestingDonor
+- (NSPoint)mouseLocationOutsideOfEventStream {
+  NSWindow* window = base::mac::ObjCCastStrict<NSWindow>(self);
+  if (g_mouse_location_override_enabled) {
+    return ui::ConvertPointFromScreenToWindow(window,
+                                              g_mouse_location_override);
+  }
+
+  return ui::ConvertPointFromScreenToWindow(window, g_mouse_location);
+}
+@end
+
+namespace {
+class NSEventSwizzler {
+ public:
+  static void Install() {
+    static NSEventSwizzler* swizzler = nullptr;
+    if (!swizzler) {
+      swizzler = new NSEventSwizzler();
+    }
+  }
+
+ protected:
+  NSEventSwizzler()
+      : mouse_location_swizzler_(new base::mac::ScopedObjCClassSwizzler(
+            [NSEvent class],
+            [FakeNSEventTestingDonor class],
+            @selector(mouseLocation))),
+        pressed_mouse_buttons_swizzler_(new base::mac::ScopedObjCClassSwizzler(
+            [NSEvent class],
+            [FakeNSEventTestingDonor class],
+            @selector(pressedMouseButtons))),
+        mouse_location_outside_of_event_stream_swizzler_(
+            new base::mac::ScopedObjCClassSwizzler(
+                [NSWindow class],
+                [FakeNSWindowTestingDonor class],
+                @selector(mouseLocationOutsideOfEventStream))) {}
+
+ private:
+  std::unique_ptr<base::mac::ScopedObjCClassSwizzler> mouse_location_swizzler_;
+  std::unique_ptr<base::mac::ScopedObjCClassSwizzler>
+      pressed_mouse_buttons_swizzler_;
+  std::unique_ptr<base::mac::ScopedObjCClassSwizzler>
+      mouse_location_outside_of_event_stream_swizzler_;
+};
+}  // namespace
+
 namespace ui_controls {
 
 void EnableUIControls() {
@@ -204,6 +415,7 @@ bool SendKeyPressNotifyWhenDone(gfx::NativeWindow window,
                                 bool alt,
                                 bool command,
                                 const base::Closure& task) {
+  DCHECK(!g_use_cgevents) << "Not implemented";
   CHECK(g_ui_controls_enabled);
   DCHECK(base::MessageLoopForUI::IsCurrent());
 
@@ -239,9 +451,8 @@ bool SendMouseMove(long x, long y) {
 // platforms.  E.g. (0,0) is upper-left.
 bool SendMouseMoveNotifyWhenDone(long x, long y, const base::Closure& task) {
   CHECK(g_ui_controls_enabled);
-  CGFloat screenHeight =
-    [[[NSScreen screens] firstObject] frame].size.height;
-  g_mouse_location = NSMakePoint(x, screenHeight - y);  // flip!
+  g_mouse_location = gfx::ScreenPointToNSPoint(gfx::Point(x, y));  // flip!
+  NSEventSwizzler::Install();
 
   NSWindow* window = WindowAtCurrentMouseLocation();
 
@@ -250,21 +461,37 @@ bool SendMouseMoveNotifyWhenDone(long x, long y, const base::Closure& task) {
     pointInWindow = ui::ConvertPointFromScreenToWindow(window, pointInWindow);
   NSTimeInterval timestamp = TimeIntervalSinceSystemStartup();
 
+  NSEventType event_type = NSMouseMoved;
+  if (g_mouse_button_down[LEFT]) {
+    event_type = NSLeftMouseDragged;
+  } else if (g_mouse_button_down[RIGHT]) {
+    event_type = NSRightMouseDragged;
+  } else if (g_mouse_button_down[MIDDLE]) {
+    event_type = NSOtherMouseDragged;
+  }
+
   NSEvent* event =
-      [NSEvent mouseEventWithType:NSMouseMoved
+      [NSEvent mouseEventWithType:event_type
                          location:pointInWindow
                     modifierFlags:0
                         timestamp:timestamp
                      windowNumber:[window windowNumber]
                           context:nil
                       eventNumber:0
-                       clickCount:0
-                         pressure:0.0];
-  [[NSApplication sharedApplication] postEvent:event atStart:NO];
+                       clickCount:(event_type == NSMouseMoved ? 0 : 1)
+                         pressure:(event_type == NSMouseMoved ? 0.0 : 1.0)];
 
   if (!task.is_null()) {
-    base::MessageLoop::current()->PostTask(
-        FROM_HERE, base::Bind(&EventQueueWatcher, task));
+    EventMonitor::Instance()->NotifyWhenEventIsProcessed(event, task);
+  }
+
+  gfx::Point gp = gfx::ScreenPointFromNSPoint(g_mouse_location);
+  CGWarpMouseCursorPosition(CGPointMake(gp.x(), gp.y()));
+
+  if (g_use_cgevents) {
+    CGEventPost(kCGSessionEventTap, [event CGEvent]);
+  } else {
+    [[NSApplication sharedApplication] postEvent:event atStart:NO];
   }
 
   return true;
@@ -284,48 +511,56 @@ bool SendMouseEventsNotifyWhenDone(MouseButton type, int state,
     return (SendMouseEventsNotifyWhenDone(type, DOWN, base::Closure()) &&
             SendMouseEventsNotifyWhenDone(type, UP, task));
   }
-  NSEventType etype = NSLeftMouseDown;
+  NSEventType event_type = NSLeftMouseDown;
   if (type == LEFT) {
     if (state == UP) {
-      etype = NSLeftMouseUp;
+      event_type = NSLeftMouseUp;
     } else {
-      etype = NSLeftMouseDown;
+      event_type = NSLeftMouseDown;
     }
   } else if (type == MIDDLE) {
     if (state == UP) {
-      etype = NSOtherMouseUp;
+      event_type = NSOtherMouseUp;
     } else {
-      etype = NSOtherMouseDown;
+      event_type = NSOtherMouseDown;
     }
   } else if (type == RIGHT) {
     if (state == UP) {
-      etype = NSRightMouseUp;
+      event_type = NSRightMouseUp;
     } else {
-      etype = NSRightMouseDown;
+      event_type = NSRightMouseDown;
     }
   } else {
+    NOTREACHED();
     return false;
   }
+  g_mouse_button_down[type] = state == DOWN;
+
   NSWindow* window = WindowAtCurrentMouseLocation();
   NSPoint pointInWindow = g_mouse_location;
   if (window)
     pointInWindow = ui::ConvertPointFromScreenToWindow(window, pointInWindow);
 
-  NSEvent* event =
-      [NSEvent mouseEventWithType:etype
-                         location:pointInWindow
-                    modifierFlags:0
-                        timestamp:TimeIntervalSinceSystemStartup()
-                     windowNumber:[window windowNumber]
-                          context:nil
-                      eventNumber:0
-                       clickCount:1
-                         pressure:(state == DOWN ? 1.0 : 0.0 )];
-  [[NSApplication sharedApplication] postEvent:event atStart:NO];
+  NSEventSwizzler::Install();
+
+  NSEvent* event = [NSEvent mouseEventWithType:event_type
+                                      location:pointInWindow
+                                 modifierFlags:0
+                                     timestamp:TimeIntervalSinceSystemStartup()
+                                  windowNumber:[window windowNumber]
+                                       context:nil
+                                   eventNumber:0
+                                    clickCount:1
+                                      pressure:(state == DOWN ? 1.0 : 0.0)];
 
   if (!task.is_null()) {
-    base::MessageLoop::current()->PostTask(
-        FROM_HERE, base::Bind(&EventQueueWatcher, task));
+    EventMonitor::Instance()->NotifyWhenEventIsProcessed(event, task);
+  }
+
+  if (g_use_cgevents) {
+    CGEventPost(kCGSessionEventTap, [event CGEvent]);
+  } else {
+    [[NSApplication sharedApplication] postEvent:event atStart:NO];
   }
 
   return true;
@@ -345,4 +580,21 @@ bool IsFullKeyboardAccessEnabled() {
   return [NSApp isFullKeyboardAccessEnabled];
 }
 
+void SetSendMouseEventsAsCGEvents(bool enable_cgevents) {
+  g_use_cgevents = enable_cgevents;
+}
+
+bool SendMouseEventsAsCGEvents() {
+  return g_use_cgevents;
+}
+
+void NotifyWhenEventIsProcessed(NSEvent* event, const base::Closure& task) {
+  EventMonitor::Instance()->NotifyWhenEventIsProcessed(event, task);
+}
+
+void SetMousePositionOverride(bool enable_override, const gfx::Point& p) {
+  g_mouse_location_override_enabled = enable_override;
+  g_mouse_location_override = gfx::ScreenPointToNSPoint(p);  // flip!
+}
+
 }  // namespace ui_controls