android: Add the target to toplevel Looper events in tracing,

base/android/trace_event_binding.cc

Index: base/android/trace_event_binding.cc
diff --git a/base/android/trace_event_binding.cc b/base/android/trace_event_binding.cc
index 8551f99f961b6c3f72164b517770d404cf559bdb..30ca55ef8881d9f1247c29cb346c28dfc0475b57 100644
--- a/base/android/trace_event_binding.cc
+++ b/base/android/trace_event_binding.cc
@@ -121,8 +121,12 @@ static void End(JNIEnv* env,
   }
 }
 
-static void BeginToplevel(JNIEnv* env, const JavaParamRef<jclass>& clazz) {
-  TRACE_EVENT_BEGIN0(kToplevelCategory, kLooperDispatchMessage);
+static void BeginToplevel(JNIEnv* env,
+                          const JavaParamRef<jclass>& clazz,
+                          const JavaParamRef<jstring>& jtarget) {
+  std::string target = ConvertJavaStringToUTF8(env, jtarget);
+  TRACE_EVENT_BEGIN1(kToplevelCategory, kLooperDispatchMessage, "target",
+                     target);
 }
 
 static void EndToplevel(JNIEnv* env, const JavaParamRef<jclass>& clazz) {