Fix processing of mouse events on MacViews.

ui/views/cocoa/bridged_native_widget.mm

Index: ui/views/cocoa/bridged_native_widget.mm
diff --git a/ui/views/cocoa/bridged_native_widget.mm b/ui/views/cocoa/bridged_native_widget.mm
index 8e47513350dc150013b5a19023ea9e969f42d8e1..5e1c24a31ce817e9516ae8f5118a2807b97e948f 100644
--- a/ui/views/cocoa/bridged_native_widget.mm
+++ b/ui/views/cocoa/bridged_native_widget.mm
@@ -14,20 +14,22 @@
 #import "base/mac/sdk_forward_declarations.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "ui/accelerated_widget_mac/window_resize_helper_mac.h"
+#include "ui/base/cocoa/cocoa_base_utils.h"
 #import "ui/base/cocoa/constrained_window/constrained_window_animation.h"
 #include "ui/base/hit_test.h"
 #include "ui/base/ime/input_method.h"
 #include "ui/base/ime/input_method_factory.h"
 #include "ui/display/display.h"
 #include "ui/display/screen.h"
+#include "ui/events/event_utils.h"
 #include "ui/gfx/geometry/dip_util.h"
 #import "ui/gfx/mac/coordinate_conversion.h"
 #import "ui/gfx/mac/nswindow_frame_controls.h"
 #import "ui/native_theme/native_theme_mac.h"
 #import "ui/views/cocoa/bridged_content_view.h"
-#import "ui/views/cocoa/drag_drop_client_mac.h"
 #import "ui/views/cocoa/cocoa_mouse_capture.h"
 #import "ui/views/cocoa/cocoa_window_move_loop.h"
+#import "ui/views/cocoa/drag_drop_client_mac.h"
 #include "ui/views/cocoa/tooltip_manager_mac.h"
 #import "ui/views/cocoa/views_nswindow_delegate.h"
 #import "ui/views/cocoa/widget_owner_nswindow_adapter.h"
@@ -323,6 +325,28 @@ NSUInteger CountBridgedWindows(NSArray* child_windows) {
   return count;
 }
 
+// Convert an |event|'s mouse point to |target_view|'s content rect, with the
+// origin at the top left of the content area.
+// If -[|event| window] is nil, original point will be treated as screen
+// coordinates.
+gfx::Point GetEventLocationInView(NSEvent* event, NSView* target_view) {
+  NSWindow* source = [event window];
+  NSWindow* target = [target_view window];
+  DCHECK(target);
+  NSPoint point_in_window = [event locationInWindow];
+  if (![target isEqual:source]) {
+    NSPoint point_in_screen =
+        source ? ui::ConvertPointFromWindowToScreen(source, point_in_window)
+               : point_in_window;
+    point_in_window =
+        ui::ConvertPointFromScreenToWindow(target, point_in_screen);
+  }
+  NSPoint point_in_view =
+      [target_view convertPoint:point_in_window fromView:nil];
+  return gfx::Point(point_in_view.x,
+                    NSHeight([target_view frame]) - point_in_view.y);
+}
+
 }  // namespace
 
 namespace views {
@@ -1061,17 +1085,93 @@ NSUInteger CountBridgedWindows(NSArray* child_windows) {
 // BridgedNativeWidget, CocoaMouseCaptureDelegate:
 
 void BridgedNativeWidget::PostCapturedEvent(NSEvent* event) {
-  [bridged_view_ processCapturedMouseEvent:event];
+  OnMouseEvent(event);
 }
 
 void BridgedNativeWidget::OnMouseCaptureLost() {
   native_widget_mac_->GetWidget()->OnMouseCaptureLost();
+  SendStoredMouseExitedEventToWidget();
 }
 
 NSWindow* BridgedNativeWidget::GetWindow() const {
   return window_;
 }
 
+void BridgedNativeWidget::OnMouseEvent(NSEvent* native_event) {
+  pendingExitEvent_.reset();
+
+  const gfx::Point location =
+      GetEventLocationInView(native_event, bridged_view_);
+  views::Widget* widget = native_widget_mac_->GetWidget();
+
+  bool event_inside_widget = false;
+  if (widget->HasHitTestMask()) {
+    gfx::Path hit_test_mask;
+    widget->GetHitTestMask(&hit_test_mask);
+    event_inside_widget = hit_test_mask.contains(location.x(), location.y());
+  } else {
+    event_inside_widget =
+        gfx::Rect(widget->GetWindowBoundsInScreen().size()).Contains(location);
+  }
+  const bool should_send_entered_event =
+      !mouse_inside_ && (event_inside_widget || HasCapture());
+  if (should_send_entered_event) {
+    ui::MouseEvent entered_event(ui::ET_MOUSE_ENTERED, location, location,
+                                 ui::EventTimeFromNative(native_event),
+                                 ui::EF_NONE, ui::EF_NONE);
+    widget->OnMouseEvent(&entered_event);
+    mouse_inside_ = true;
+  }
+
+  if (!mouse_inside_) {
+    return [bridged_view_ passMouseEventToSuperview:native_event];
+  }
+
+  if ([native_event type] == NSScrollWheel) {
+    ui::ScrollEvent event(native_event);
+    event.set_location(location);
+    widget->OnScrollEvent(&event);
+  } else if ([native_event type] != NSMouseEntered &&
+             [native_event type] != NSMouseExited) {
+    ui::MouseEvent event(native_event);
+    event.set_location(location);
+    widget->OnMouseEvent(&event);
+  }
+  // We could get an NSMouseExited with its location within the bounds of the
+  // view.
+  const bool should_send_exited_event =
+      !HasCapture() &&
+      (!event_inside_widget || [native_event type] == NSMouseExited);
+  // If we don't need to send the ET_MOUSE_EXITED event immediately, postpone it
+  // until later.
+  const bool should_create_exited_event =
+      should_send_exited_event || !event_inside_widget;
+
+  if (should_create_exited_event) {
+    // The tracking area will send an exit event even during a drag, which isn't
+    // how the event flow for drags should work. This stores the exit event, and
+    // sends it when the drag completes instead.
+    pendingExitEvent_.reset(new ui::MouseEvent(
+        ui::ET_MOUSE_EXITED, location, location,
+        ui::EventTimeFromNative(native_event), ui::EF_NONE, ui::EF_NONE));
+  }
+
+  if (should_send_exited_event) {
+    SendStoredMouseExitedEventToWidget();
+  } else {
+    [bridged_view_ updateTooltipIfRequiredAt:location];
+  }
+}
+
+void BridgedNativeWidget::SendStoredMouseExitedEventToWidget() {
+  if (pendingExitEvent_) {
+    mouse_inside_ = false;
+    auto exited_event = std::move(pendingExitEvent_);
+    native_widget_mac_->GetWidget()->OnMouseEvent(exited_event.get());
+    [bridged_view_ hideTooltipIfRequired];
+  }
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // BridgedNativeWidget, FocusChangeListener: