cocoa: use window-scale to support video scaling functionality

In the cocoa backend you can use cmd+0/1/2 to scale the window. This commit
makes it use the new window-scale functionality.

video/out/cocoa/mpvadapter.h

@@ -23,6 +23,7 @@
 - (void)signalMouseMovement:(NSPoint)point;
 - (void)putKey:(int)mpkey withModifiers:(int)modifiers;
 - (void)putAxis:(int)mpkey delta:(float)delta;
+- (void)putCommand:(char*)cmd;
 - (void)performAsyncResize:(NSSize)size;
 
 - (BOOL)isInFullScreenMode;

video/out/cocoa/window.m

@@ -97,12 +97,8 @@
 
 - (void)mulSize:(float)multiplier
 {
-    if (![self.adapter isInFullScreenMode]) {
-        NSSize size = [self.adapter videoSize];
-        size.width  *= multiplier;
-        size.height *= multiplier;
-        [self setCenteredContentSize:size];
-    }
+    char *cmd = ta_asprintf(NULL, "set window-scale %f", multiplier);
+    [self.adapter putCommand:cmd];
 }
 
 - (int)titleHeight

video/out/cocoa_common.m

@@ -629,6 +629,13 @@ int vo_cocoa_cgl_color_size(struct vo *vo)
     mp_input_put_axis(self.vout->input_ctx, mpkey, delta);
 }
 
+- (void)putCommand:(char*)cmd
+{
+    mp_cmd_t *cmdt = mp_input_parse_cmd(self.vout->input_ctx, bstr0(cmd), "");
+    mp_input_queue_cmd(self.vout->input_ctx, cmdt);
+    ta_free(cmd);
+}
+
 - (void)performAsyncResize:(NSSize)size {
     vo_cocoa_resize_redraw(self.vout, size.width, size.height);
 }