Allow the configs parameter for eglChooseConfig to be null in shadow

Most of the time, the output parameters for EGL methods are
expected to be non-null. But the `configs` parameter of
`eglChooseConfig` is one of the exceptions. When `configs` is
not null, `eglChooseConfig` fills that with the first
`configSize` configs and fills `numConfig` with the number of
returned configs (no more than `configsSize`). But when `configs`
is_ `null` it fills `numConfigs` with the number of _matching_
configs, ignoring `configsSize`:
https://registry.khronos.org/EGL/sdk/docs/man/html/eglChooseConfig.xhtml

The Android code wrapping this API checks that `attrib_list` and
`num_configs` output arrays are not null, but allows `configs`
to be null (see frameworks/base/core/jni/android_opengl_EGL14.cpp).

PiperOrigin-RevId: 631820937

robolectric/src/test/java/org/robolectric/shadows/ShadowEGL14Test.java

@@ -27,15 +27,27 @@ public void eglGetDisplay() {
   }
 
   @Test
-  public void eglChooseConfig() {
+  public void eglChooseConfig_retrieveConfigs() {
     EGLDisplay display = EGL14.eglGetDisplay(EGL14.EGL_DEFAULT_DISPLAY);
+    // When the config array is not null, numConfig is filled with the number of configs returned
+    // (up to the size of the config array).
     EGLConfig[] configs = new EGLConfig[1];
     int[] numConfig = new int[1];
     assertThat(EGL14.eglChooseConfig(display, new int[0], 0, configs, 0, 1, numConfig, 0)).isTrue();
     assertThat(numConfig[0]).isGreaterThan(0);
     assertThat(configs[0]).isNotNull();
   }
 
+  @Test
+  public void eglChooseConfig_countMatching() {
+    EGLDisplay display = EGL14.eglGetDisplay(EGL14.EGL_DEFAULT_DISPLAY);
+    // When the config array is null, numConfig is filled with the total number of configs matched.
+    EGLConfig[] configs = null;
+    int[] numConfig = new int[1];
+    assertThat(EGL14.eglChooseConfig(display, new int[0], 0, configs, 0, 0, numConfig, 0)).isTrue();
+    assertThat(numConfig[0]).isGreaterThan(0);
+  }
+
   @Test
   public void eglCreateContext_v2() {
     EGLDisplay display = EGL14.eglGetDisplay(EGL14.EGL_DEFAULT_DISPLAY);

shadows/framework/src/main/java/org/robolectric/shadows/ShadowEGL14.java

@@ -37,7 +37,11 @@ protected static boolean eglChooseConfig(
       int configSize,
       int[] numConfig,
       int numConfigOffset) {
-    configs[configsOffset] = createEglConfig();
+    // The configs array here can be null, in which case the numConfig output is supposed to be
+    // set to the number of matching configs instead of the number of returned configs.
+    if (configs != null) {
+      configs[configsOffset] = createEglConfig();
+    }
     numConfig[numConfigOffset] = 1;
     return true;
   }