Merge "Remove 1.3s "Waiting for Debugger" delay" am: e5527c234e am: 7f45627502

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/2305923

Change-Id: I148078dd054ed8efa38e8aff06ffdd40216a9882
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>

core/java/android/os/Debug.java

@@ -981,6 +981,43 @@ public final class Debug
     }
 
 
+    /**
+     * Wait until a debugger attaches. As soon as a debugger attaches,
+     * suspend all Java threads and send VM_START (a.k.a VM_INIT)
+     * packet.
+     *
+     * @hide
+     */
+    public static void suspendAllAndSendVmStart() {
+        if (!VMDebug.isDebuggingEnabled()) {
+            return;
+        }
+
+        // if DDMS is listening, inform them of our plight
+        System.out.println("Sending WAIT chunk");
+        byte[] data = new byte[] { 0 };     // 0 == "waiting for debugger"
+        Chunk waitChunk = new Chunk(ChunkHandler.type("WAIT"), data, 0, 1);
+        DdmServer.sendChunk(waitChunk);
+
+        // We must wait until a debugger is connected (debug socket is
+        // open and at least one non-DDM JDWP packedt has been received.
+        // This guarantees that oj-libjdwp has been attached and that
+        // ART's default implementation of suspendAllAndSendVmStart has
+        // been replaced with an implementation that will suspendAll and
+        // send VM_START.
+        System.out.println("Waiting for debugger first packet");
+        while (!isDebuggerConnected()) {
+            try {
+                Thread.sleep(100);
+            } catch (InterruptedException ie) {
+            }
+        }
+
+        System.out.println("Debug.suspendAllAndSentVmStart");
+        VMDebug.suspendAllAndSendVmStart();
+        System.out.println("Debug.suspendAllAndSendVmStart, resumed");
+    }
+
     /**
      * Wait until a debugger attaches.  As soon as the debugger attaches,
      * this returns, so you will need to place a breakpoint after the