sdk: Guard activateTrigger in Java on sdk registration

Calling activateTrigger before register() SIGTRAPs in
TracingMuxerFake. Callers worked around this by pre-checking
getAttempedSystemRegistration(), but that check was stricter than it
needed to be and silently dropped triggers against in-process
registrations, which the native muxer handles safely.

Move the guard inside activateTrigger and key it on any register()
call. The return value now tells the caller whether the trigger
reaches the system backend, so callers can skip the pre-check and
only fall back to trigger_perfetto when it returns false.

Change-Id: I13b0ee5f31d63271181569610e587de70b2351c4

src/android_sdk/java/main/dev/perfetto/sdk/PerfettoTrace.java

diff --git a/src/android_sdk/java/main/dev/perfetto/sdk/PerfettoTrace.java b/src/android_sdk/java/main/dev/perfetto/sdk/PerfettoTrace.java
index dabc496..4690d4a 100644
--- a/src/android_sdk/java/main/dev/perfetto/sdk/PerfettoTrace.java
+++ b/src/android_sdk/java/main/dev/perfetto/sdk/PerfettoTrace.java
@@ -46,6 +46,7 @@
   private static final PerfettoNativeMemoryCleaner sNativeMemoryCleaner =
       new PerfettoNativeMemoryCleaner();
 
+  private static final AtomicBoolean sAttemptedRegistration = new AtomicBoolean(false);
   private static final AtomicBoolean sAttemptedSystemRegistration = new AtomicBoolean(false);
 
   /** For fetching the next flow event id in a process. */
@@ -302,17 +303,26 @@
     return native_get_thread_track_uuid(tid);
   }
 
-  /** Activates a trigger by name {@code triggerName} with expiry in {@code ttlMs}. */
-  public static void activateTrigger(String triggerName, int ttlMs) {
+  /**
+   * Activates a trigger by name {@code triggerName} with expiry in {@code ttlMs}. Returns
+   * {@code true} iff the trigger was forwarded to the system backend; on {@code false} the
+   * caller should fall back to {@code trigger_perfetto}.
+   */
+  public static boolean activateTrigger(String triggerName, int ttlMs) {
+    if (!sAttemptedRegistration.get()) {
+      return false;
+    }
     native_activate_trigger(triggerName, ttlMs);
+    return sAttemptedSystemRegistration.get();
   }
 
   /** Registers the process with Perfetto. */
   public static void register(boolean isBackendInProcess) {
+    native_register(isBackendInProcess);
+    sAttemptedRegistration.set(true);
     if (!isBackendInProcess) {
         sAttemptedSystemRegistration.set(true);
     }
-    native_register(isBackendInProcess);
   }
 
   /** Registers the process with Perfetto and enable additional debug checks on the Java side. */

src/android_sdk/java/test/dev/perfetto/sdk/test/PerfettoTraceTest.java

diff --git a/src/android_sdk/java/test/dev/perfetto/sdk/test/PerfettoTraceTest.java b/src/android_sdk/java/test/dev/perfetto/sdk/test/PerfettoTraceTest.java
index dfcf63b..1647e1d 100644
--- a/src/android_sdk/java/test/dev/perfetto/sdk/test/PerfettoTraceTest.java
+++ b/src/android_sdk/java/test/dev/perfetto/sdk/test/PerfettoTraceTest.java
@@ -729,29 +729,27 @@
   @Test
   public void testActivateTrigger() throws Exception {
     TraceConfig traceConfig = getTriggerTraceConfig(FOO, FOO);
-
     PerfettoTrace.Session session = new PerfettoTrace.Session(true, traceConfig.toByteArray());
 
     PerfettoTrace.instant(FOO_CATEGORY, "event_trigger").emit();
 
-    PerfettoTrace.activateTrigger(FOO, 1000);
+    // setUp() registered with isBackendInProcess=true: the trigger fires against
+    // the in-process session but the return is false (system not registered).
+    assertThat(PerfettoTrace.activateTrigger(FOO, 1000)).isFalse();
 
     byte[] traceBytes = session.close();
 
     Trace trace = Trace.parseFrom(traceBytes);
 
-    boolean hasTrackEvent = false;
-    boolean hasChromeLatencyInfo = false;
-
+    boolean hasTrigger = false;
     for (TracePacket packet : trace.getPacketList()) {
-      TrackEvent event;
-      if (packet.hasTrackEvent()) {
-        hasTrackEvent = true;
+      if (packet.hasTrigger() && FOO.equals(packet.getTrigger().getTriggerName())) {
+        hasTrigger = true;
       }
-
       collectInternedData(packet);
     }
 
+    assertThat(hasTrigger).isTrue();
     assertThat(mCategoryNames).contains(FOO);
   }