gdk: Add GDK_DISABLE=aerosnap

Disables the Aerosnap hook for Windows which is particularly useful
when debugging because the aerosnap hook slows down keyboard input.

docs/reference/gtk/running.md

@@ -358,6 +358,9 @@ disable certain features.
 `color-mgmt`
 : Disable color management
 
+`aerosnap`
+: Disable Aerosnap support on Windows
+
 ### `GDK_GL_DISABLE`
 
 This variable can be set to a list of values, which cause GDK to

gdk/gdk.c

@@ -158,6 +158,7 @@ static const GdkDebugKey gdk_feature_keys[] = {
   { "dmabuf",     GDK_FEATURE_DMABUF,           "Disable dmabuf support" },
   { "offload",    GDK_FEATURE_OFFLOAD,          "Disable graphics offload" },
   { "color-mgmt", GDK_FEATURE_COLOR_MANAGEMENT, "Disable color management" },
+  { "aerosnap",   GDK_FEATURE_AEROSNAP,         "Disable Aerosnap support on Windows" },
 };
 
 

gdk/gdkdebugprivate.h

@@ -64,6 +64,7 @@ typedef enum {
   GDK_FEATURE_DMABUF           = 1 << 7,
   GDK_FEATURE_OFFLOAD          = 1 << 8,
   GDK_FEATURE_COLOR_MANAGEMENT = 1 << 9,
+  GDK_FEATURE_AEROSNAP         = 1 << 10,
 } GdkFeatures;
 
 #define GDK_ALL_FEATURES ((1 << 10) - 1)

gdk/win32/gdkevents-win32.c

@@ -391,6 +391,9 @@ set_up_low_level_keyboard_hook (GdkDisplay *display)
 {
   HHOOK hook_handle;
 
+  if (!gdk_has_feature (GDK_FEATURE_AEROSNAP))
+    return;
+
   if (GDK_WIN32_DISPLAY (display)->event_record->aerosnap_keyboard_hook != NULL)
     return;