Support Mac key equivalent Cmd+Period

On Mac Cmd+Period isa special key combination which never got delived
to Qt application. We can intercept these special keyboard shortcuts in
the performKeyEquivalent function.

Task-number: QTBUG-11386
Change-Id: I680385bde07b2810e8bde86ec9fbbe7e09156c84
Reviewed-by: Gabriel de Dietrich <gabriel.dedietrich@digia.com>

src/plugins/platforms/cocoa/qnsview.h

@@ -113,6 +113,7 @@ QT_END_NAMESPACE
 - (void)handleKeyEvent:(NSEvent *)theEvent eventType:(int)eventType;
 - (void)keyDown:(NSEvent *)theEvent;
 - (void)keyUp:(NSEvent *)theEvent;
+- (BOOL)performKeyEquivalent:(NSEvent *)theEvent;
 
 - (void)registerDragTypes;
 - (NSDragOperation)handleDrag:(id <NSDraggingInfo>)sender;

src/plugins/platforms/cocoa/qnsview.mm

@@ -972,6 +972,23 @@ static QTouchDevice *touchDevice = 0;
     [self handleKeyEvent:nsevent eventType:int(QEvent::KeyRelease)];
 }
 
+- (BOOL)performKeyEquivalent:(NSEvent *)nsevent
+{
+    NSString *chars = [nsevent charactersIgnoringModifiers];
+
+    if ([nsevent type] == NSKeyDown && [chars length] > 0) {
+        QChar ch = [chars characterAtIndex:0];
+        Qt::Key qtKey = qt_mac_cocoaKey2QtKey(ch);
+        // check for Command + Key_Period
+        if ([nsevent modifierFlags] & NSCommandKeyMask
+                && qtKey == Qt::Key_Period) {
+            [self handleKeyEvent:nsevent eventType:int(QEvent::KeyPress)];
+            return YES;
+        }
+    }
+    return [super performKeyEquivalent:nsevent];
+}
+
 - (void)flagsChanged:(NSEvent *)nsevent
 {
     ulong timestamp = [nsevent timestamp] * 1000;