refactor: use stubs for gdk-pixbuf dependency

BUILD.gn

@@ -87,7 +87,10 @@ if (is_linux) {
   # implementation. In future, this file can be extended to contain
   # gtk4 stubs to switch gtk version in runtime.
   generate_stubs("electron_gtk_stubs") {
-    sigs = [ "shell/browser/ui/electron_gtk.sigs" ]
+    sigs = [
+      "shell/browser/ui/electron_gdk_pixbuf.sigs",
+      "shell/browser/ui/electron_gtk.sigs",
+    ]
     extra_header = "shell/browser/ui/electron_gtk.fragment"
     output_name = "electron_gtk_stubs"
     public_deps = [ "//ui/gtk:gtk_config" ]

patches/chromium/.patches

@@ -111,3 +111,4 @@ make_gtk_getlibgtk_public.patch
 build_disable_print_content_analysis.patch
 custom_protocols_plzserviceworker.patch
 feat_filter_out_non-shareable_windows_in_the_current_application_in.patch
+make_gtk_getlibgdkpixbuf_public.patch

patches/chromium/make_gtk_getlibgdkpixbuf_public.patch

@@ -0,0 +1,50 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Raymond Zhao <7199958+rzhao271@users.noreply.github.com>
+Date: Wed, 15 Jun 2022 17:59:18 +0000
+Subject: Make gtk::GetLibGdkPixbuf public
+
+Allows Electron to fetch libgdk_pixbuf during run-time
+rather than having to link to it statically.
+
+diff --git a/ui/gtk/gtk_compat.cc b/ui/gtk/gtk_compat.cc
+index 40b706ed7cde206e98274025148604760b7477f9..65b097cfab72b92f301968715eb218ef0e468567 100644
+--- a/ui/gtk/gtk_compat.cc
++++ b/ui/gtk/gtk_compat.cc
+@@ -66,11 +66,6 @@ void* GetLibGio() {
+   return libgio;
+ }
+
+-void* GetLibGdkPixbuf() {
+-  static void* libgdk_pixbuf = DlOpen("libgdk_pixbuf-2.0.so.0");
+-  return libgdk_pixbuf;
+-}
+-
+ void* GetLibGdk3() {
+   static void* libgdk3 = DlOpen("libgdk-3.so.0");
+   return libgdk3;
+@@ -128,6 +123,11 @@ gfx::Insets InsetsFromGtkBorder(const GtkBorder& border) {
+
+ }  // namespace
+
++void* GetLibGdkPixbuf() {
++  static void* libgdk_pixbuf = DlOpen("libgdk_pixbuf-2.0.so.0");
++  return libgdk_pixbuf;
++}
++
+ void* GetLibGtk() {
+   if (GtkCheckVersion(4))
+     return GetLibGtk4();
+diff --git a/ui/gtk/gtk_compat.h b/ui/gtk/gtk_compat.h
+index 2245974f91be4a691d82f54b55e12e44ae2000c5..37720be9e393d192b3b7db13a007431a9ce77ddc 100644
+--- a/ui/gtk/gtk_compat.h
++++ b/ui/gtk/gtk_compat.h
+@@ -34,6 +34,9 @@ using SkColor = uint32_t;
+
+ namespace gtk {
+
++// Get handle to the currently loaded gdk_pixbuf library in the process.
++void* GetLibGdkPixbuf();
++
+ // Get handle to the currently loaded gtk library in the process.
+ void* GetLibGtk();
+

shell/browser/electron_browser_main_parts.cc

@@ -371,6 +371,11 @@ void ElectronBrowserMainParts::ToolkitInitialized() {
     electron::UninitializeElectron_gtk();
   }
 
+  electron::InitializeElectron_gdk_pixbuf(gtk::GetLibGdkPixbuf());
+  if (!electron::IsElectron_gdk_pixbufInitialized()) {
+    electron::UninitializeElectron_gdk_pixbuf();
+  }
+
   // Chromium does not respect GTK dark theme setting, but they may change
   // in future and this code might be no longer needed. Check the Chromium
   // issue to keep updated:

shell/browser/ui/electron_gdk_pixbuf.sigs

@@ -0,0 +1,3 @@
+GdkPixbuf* gdk_pixbuf_new(GdkColorspace colorspace, gboolean has_alpha, int bits_per_sample, int width, int height)
+GdkPixbuf* gdk_pixbuf_scale_simple(const GdkPixbuf* src, int dest_width, int dest_height, GdkInterpType interp_type)
+guchar* gdk_pixbuf_get_pixels(const GdkPixbuf* pixbuf)

shell/browser/ui/electron_gtk.fragment

@@ -1 +1,2 @@
-#include <gtk/gtk.h>
+#include <gdk-pixbuf/gdk-pixbuf.h>
+#include <gtk/gtk.h>

shell/browser/ui/electron_gtk.sigs

@@ -4,4 +4,4 @@ void gtk_native_dialog_show(GtkNativeDialog* self);
 void gtk_native_dialog_hide(GtkNativeDialog* self);
 gint gtk_native_dialog_run(GtkNativeDialog* self);
 void gtk_native_dialog_destroy(GtkNativeDialog* self);
-GType gtk_native_dialog_get_type(void);
+GType gtk_native_dialog_get_type(void);

shell/browser/ui/gtk_util.cc

@@ -12,6 +12,7 @@
 
 #include "base/no_destructor.h"
 #include "base/strings/string_number_conversions.h"
+#include "electron/electron_gtk_stubs.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "third_party/skia/include/core/SkUnPreMultiply.h"

shell/browser/ui/message_box_gtk.cc

@@ -11,6 +11,7 @@
 #include "base/no_destructor.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
+#include "electron/electron_gtk_stubs.h"
 #include "shell/browser/browser.h"
 #include "shell/browser/native_window_observer.h"
 #include "shell/browser/native_window_views.h"