fix: remove white screen flicker by disabling compositor recycling

fix #19858

patches/chromium/.patches

@@ -73,3 +73,4 @@ build_win_disable_zc_twophase.patch
 disable_color_correct_rendering.patch
 add_contentgpuclient_precreatemessageloop_callback.patch
 fix_use_weakptr_to_detect_deletion.patch
+disable_compositor_recycling.patch

patches/chromium/disable_compositor_recycling.patch

@@ -0,0 +1,20 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Andy Locascio <andy@slack-corp.com>
+Date: Wed, 21 Aug 2019 12:09:10 -0700
+Subject: fix: disabling compositor recycling
+
+Compositor recycling is useful for Chrome because there can be many tabs and spinning up a compositor for each one would be costly. In practice, Chrome uses the parent compositor code path of browser_compositor_view_mac.mm; the NSView of each tab is detached when it's hidden and attached when it's shown. For Electron, there is no parent compositor, so we're forced into the "own compositor" code path, which seems to be non-optimal and pretty ruthless in terms of the release of resources. Electron has no real concept of multiple tabs per window, so it should be okay to disable this ruthless recycling altogether in Electron.
+
+diff --git a/content/browser/renderer_host/browser_compositor_view_mac.mm b/content/browser/renderer_host/browser_compositor_view_mac.mm
+index 59e58d693c971742951434f6582140d9179235f2..135e7a384a560f55e5201f108fe1ac2db621fbca 100644
+--- a/content/browser/renderer_host/browser_compositor_view_mac.mm
++++ b/content/browser/renderer_host/browser_compositor_view_mac.mm
+@@ -209,7 +209,7 @@
+ }
+
+ void BrowserCompositorMac::SetRenderWidgetHostIsHidden(bool hidden) {
+-  render_widget_host_is_hidden_ = hidden;
++  render_widget_host_is_hidden_ = false;
+   UpdateState();
+ }
+

patches/chromium/printing.patch

@@ -581,7 +581,7 @@ index 71c0c15217b62cd7a6087c6d9ae50481f9041d5f..18d853d7f808aaf816de86e8c5b82317
  #if BUILDFLAG(ENABLE_PRINT_PREVIEW)
    // Set options for print preset from source PDF document.
 diff --git a/printing/print_settings_conversion.cc b/printing/print_settings_conversion.cc
-index 2563ae6a87b2354ff2f2b45c17f61d2f44910efa..1f34f905791f38a44ae8c892cc9cfb38d15b659d 100644
+index 2563ae6a87b2354ff2f2b45c17f61d2f44910efa..a7c61e5286659c51579c6b50cf5cc52c10433062 100644
 --- a/printing/print_settings_conversion.cc
 +++ b/printing/print_settings_conversion.cc
 @@ -190,11 +190,12 @@ bool PrintSettingsFromJobSettings(const base::Value& job_settings,