Fix flash of page while resizing devtools NSSplitView divider.

brightray/browser/mac/bry_inspectable_web_contents_view.h

@@ -2,7 +2,8 @@
 
 @class BRYInspectableWebContentsViewPrivate;
 
-@interface BRYInspectableWebContentsView : NSView <NSWindowDelegate> {
+@interface BRYInspectableWebContentsView
+    : NSView<NSWindowDelegate, NSSplitViewDelegate> {
 @private
   BRYInspectableWebContentsViewPrivate *_private;
 }

brightray/browser/mac/bry_inspectable_web_contents_view.mm

@@ -10,10 +10,34 @@
 
 using namespace brightray;
 
+@interface GraySplitView : NSSplitView {
+  BOOL dividerHidden_;
+}
+@property(assign, nonatomic) BOOL dividerHidden;
+- (NSColor*)dividerColor;
+- (CGFloat)dividerThickness;
+@end
+
+
+@implementation GraySplitView
+
+@synthesize dividerHidden = dividerHidden_;
+
+- (NSColor*)dividerColor {
+  return [NSColor darkGrayColor];
+}
+
+- (CGFloat)dividerThickness {
+  return dividerHidden_ ? 0 : [super dividerThickness];
+}
+
+@end
+
+
 @interface BRYInspectableWebContentsViewPrivate : NSObject {
 @public
   InspectableWebContentsViewMac *inspectableWebContentsView;
-  NSSplitView *splitView;
+  GraySplitView *splitView;
   NSWindow *window;
   BOOL visible;
 }
@@ -45,7 +69,8 @@ void SetActive(content::WebContents* web_contents, bool active) {
 
   _private = [[BRYInspectableWebContentsViewPrivate alloc] init];
   _private->inspectableWebContentsView = inspectableWebContentsView;
-  _private->splitView = [[NSSplitView alloc] init];
+  _private->splitView = [[GraySplitView alloc] init];
+  _private->splitView.delegate = self;
 
   [self addSubview:_private->splitView];
   _private->splitView.autoresizingMask = NSViewWidthSizable | NSViewHeightSizable;
@@ -203,6 +228,12 @@ void SetActive(content::WebContents* web_contents, bool active) {
   [NSNotificationCenter.defaultCenter addObserver:self selector:@selector(windowDidResignKey:) name:NSWindowDidResignKeyNotification object:newWindow];
 }
 
+#pragma mark - NSSplitViewDelegate
+
+-(void)splitViewWillResizeSubviews:(NSNotification *)notification {
+  [[_private->splitView window] disableScreenUpdatesUntilFlush];
+}
+
 #pragma mark - NSWindowDelegate
 
 - (BOOL)windowShouldClose:(id)sender {
@@ -221,4 +252,4 @@ void SetActive(content::WebContents* web_contents, bool active) {
 @end
 
 @implementation BRYInspectableWebContentsViewPrivate
-@end
+@end