[Feat] (Plugin, P11 B1): the broker presents the PairBind pair at hand-off (PairBindFrames, the encoder's bytes) and answers v2 with that flag and the apply core its supervisor announced; the helper passes MOBILEGL_IPC_FD_PAIRED=1 on, and Java no longer re-derives the reserved core

tools/trace_replay/PairBindFramesTest.java

@@ -0,0 +1,47 @@
+package top.mobilegl.plugin;
+
+/**
+ * Host-side checks for PairBindFrames, the broker's hand-off PairBinds (P11 B1): the frame header and
+ * the nonce's place. That the prefixes ARE the native encoder's bytes is ServerSpawnTest's
+ * TheBrokersPairBindTemplatesAreTheEncoders (it reads them out of PairBindFrames.java). Run by
+ * tools/trace_replay/test_android_lifecycle.py with plain javac; assert-free like its siblings.
+ */
+public final class PairBindFramesTest {
+    private static int failures = 0;
+
+    private static void expect(String what, Object actual, Object expected) {
+        if (expected == null ? actual == null : expected.equals(actual)) return;
+        ++failures;
+        System.err.println(what + "\n  got:      [" + actual + "]\n  expected: [" + expected + "]");
+    }
+
+    private static int littleEndian(byte[] b, int offset) {
+        return (b[offset] & 0xff) | (b[offset + 1] & 0xff) << 8 | (b[offset + 2] & 0xff) << 16 | (b[offset + 3] & 0xff) << 24;
+    }
+
+    public static void main(String[] args) {
+        byte[] nonce = new byte[PairBindFrames.NONCE_BYTES];
+        for (int i = 0; i < nonce.length; i++) nonce[i] = (byte) (0xA0 + i);
+        for (boolean aux : new boolean[]{false, true}) {
+            byte[] frame = PairBindFrames.frame(nonce, aux);
+            String role = aux ? "aux" : "control";
+            expect(role + ": the frame magic is Framing.h's, little-endian", littleEndian(frame, 0), 0x464C474D);
+            expect(role + ": the length field is the payload's", littleEndian(frame, 4), frame.length - 8);
+            expect(role + ": the payload is the encoder's size (64 control, 68 aux)", frame.length - 8, aux ? 68 : 64);
+            expect(role + ": the envelope carries the MGLC identifier", new String(frame, 12, 4, java.nio.charset.StandardCharsets.US_ASCII), "MGLC");
+            byte[] tail = java.util.Arrays.copyOfRange(frame, frame.length - 16, frame.length);
+            expect(role + ": the nonce is the last 16 bytes", java.util.Arrays.toString(tail), java.util.Arrays.toString(nonce));
+        }
+        try {
+            PairBindFrames.frame(new byte[8], false);
+            ++failures;
+            System.err.println("a short nonce was framed");
+        } catch (IllegalArgumentException expected) {
+        }
+        if (failures != 0) {
+            System.err.println("PairBindFramesTest: " + failures + " failure(s)");
+            System.exit(1);
+        }
+        System.out.println("PairBindFramesTest: all checks passed");
+    }
+}