Bug 1297845 - Initialize gtk in GPU process. r=acomminos

MozReview-Commit-ID: EngQvL6h3EU

gfx/ipc/GPUParent.cpp

@@ -19,6 +19,7 @@
 #include "nsDebugImpl.h"
 #include "mozilla/layers/LayerTreeOwnerTracker.h"
 #include "ProcessUtils.h"
+#include "prenv.h"
 #include "VRManager.h"
 #include "VRManagerParent.h"
 #include "VsyncBridgeParent.h"
@@ -26,6 +27,9 @@
 # include "DeviceManagerD3D9.h"
 # include "mozilla/gfx/DeviceManagerDx.h"
 #endif
+#ifdef MOZ_WIDGET_GTK
+# include <gtk/gtk.h>
+#endif
 
 namespace mozilla {
 namespace gfx {
@@ -100,6 +104,26 @@ GPUParent::RecvInit(nsTArray<GfxPrefSetting>&& prefs,
   }
 #endif
 
+#if defined(MOZ_WIDGET_GTK)
+  char* display_name = PR_GetEnv("DISPLAY");
+  if (display_name) {
+    int argc = 3;
+    char option_name[] = "--display";
+    char* argv[] = {
+      // argv0 is unused because g_set_prgname() was called in
+      // XRE_InitChildProcess().
+      nullptr,
+      option_name,
+      display_name,
+      nullptr
+    };
+    char** argvp = argv;
+    gtk_init(&argc, &argvp);
+  } else {
+    gtk_init(nullptr, nullptr);
+  }
+#endif
+
   // Send a message to the UI process that we're done.
   GPUDeviceData data;
   RecvGetDeviceStatus(&data);