Always invalidate whole NSView when switching to GPU mode

content/browser/renderer_host/render_widget_host_view_mac.mm

Index: content/browser/renderer_host/render_widget_host_view_mac.mm
diff --git a/content/browser/renderer_host/render_widget_host_view_mac.mm b/content/browser/renderer_host/render_widget_host_view_mac.mm
index 68a1125825e38ee2918d6ac7dc297ee9565354dd..54132dfa89a96b43a3675a5e514245db42f3f697 100644
--- a/content/browser/renderer_host/render_widget_host_view_mac.mm
+++ b/content/browser/renderer_host/render_widget_host_view_mac.mm
@@ -1237,8 +1237,7 @@ void RenderWidgetHostViewMac::GotAcceleratedFrame() {
 
     // Need to wipe the software view with transparency to expose the GL
     // underlay. Invalidate the whole window to do that.
-    if (!about_to_validate_and_paint_)
-      [cocoa_view_ setNeedsDisplay:YES];
+    [cocoa_view_ setNeedsDisplay:YES];
 
     // Delete software backingstore.
     BackingStoreManager::RemoveBackingStore(render_widget_host_);