MacViews: Implement Tab Dragging

ui/views/cocoa/bridged_content_view.mm

Index: ui/views/cocoa/bridged_content_view.mm
diff --git a/ui/views/cocoa/bridged_content_view.mm b/ui/views/cocoa/bridged_content_view.mm
index 6b53860e202bfe7ff39ef2d021a92653b57c4382..57b9c434577dcbad31c6fc62d296e889dd949020 100644
--- a/ui/views/cocoa/bridged_content_view.mm
+++ b/ui/views/cocoa/bridged_content_view.mm
@@ -35,6 +35,13 @@ namespace {
 NSString* const kFullKeyboardAccessChangedNotification =
     @"com.apple.KeyboardUIModeDidChange";
 
+// We're sending simulated mouse events in CocoaWindowMoveLoop, and don't want
+// BridgedContentView to react when we're starting/ending the RunMoveLoop.
+// When reattaching the dragged tab we're sending the mouse down event to the
+// parent window we don't have the pointer to, so this flag is global for the
+// RunMoveLoop.
+bool g_ignore_mouse_events = false;
+
 // Returns true if all four corners of |rect| are contained inside |path|.
 bool IsRectInsidePath(NSRect rect, NSBezierPath* path) {
   return [path containsPoint:rect.origin] &&
@@ -276,6 +283,10 @@ base::string16 AttributedSubstringForRangeHelper(
   return self;
 }
 
++ (void)setIgnoreMouseEvents:(BOOL)flag {
+  g_ignore_mouse_events = flag;
+}
+
 - (void)clearView {
   textInputClient_ = nullptr;
   hostedView_ = nullptr;
@@ -459,7 +470,7 @@ base::string16 AttributedSubstringForRangeHelper(
 // Translates the location of |theEvent| to toolkit-views coordinates and passes
 // the event to NativeWidgetMac for handling.
 - (void)mouseEvent:(NSEvent*)theEvent {
-  if (!hostedView_)
+  if (!hostedView_ || g_ignore_mouse_events)
     return;
 
   ui::MouseEvent event(theEvent);