Android: Add support for TraceEvent before the native library is loaded.

base/android/early_trace_event_binding.cc

Index: base/android/early_trace_event_binding.cc
diff --git a/base/android/early_trace_event_binding.cc b/base/android/early_trace_event_binding.cc
new file mode 100644
index 0000000000000000000000000000000000000000..19e5d8d62987fe6da9ddd2e1470a1e55ae144014
--- /dev/null
+++ b/base/android/early_trace_event_binding.cc
@@ -0,0 +1,46 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/android/early_trace_event_binding.h"
+
+#include <stdint.h>
+
+#include "base/android/jni_string.h"
+#include "base/time/time.h"
+#include "base/trace_event/trace_event.h"
+#include "jni/EarlyTraceEvent_jni.h"
+
+namespace base {
+namespace android {
+
+const char kEarlyJavaCategory[] = "EarlyJava";
+
+static jlong GetTimeTicksNowUs(JNIEnv* env, const JavaParamRef<jclass>& clazz) {
+  return TimeTicks::Now().ToInternalValue();
+}
+
+static void RecordEarlyEvent(JNIEnv* env,
+                             const JavaParamRef<jclass>& clazz,
+                             const JavaParamRef<jstring>& jname,
+                             jlong begin_time_ms,
+                             jlong end_time_ms,
+                             jint thread_id) {
+  std::string name = ConvertJavaStringToUTF8(env, jname);
+  int64_t begin_us = begin_time_ms * 1000;
+  int64_t end_us = end_time_ms * 1000;
+
+  INTERNAL_TRACE_EVENT_ADD_WITH_ID_TID_AND_TIMESTAMP(
+      TRACE_EVENT_PHASE_BEGIN, kEarlyJavaCategory, name.c_str(),
+      trace_event_internal::kNoId, thread_id, begin_us, TRACE_EVENT_FLAG_COPY);
+  INTERNAL_TRACE_EVENT_ADD_WITH_ID_TID_AND_TIMESTAMP(
+      TRACE_EVENT_PHASE_END, kEarlyJavaCategory, name.c_str(),
+      trace_event_internal::kNoId, thread_id, end_us, TRACE_EVENT_FLAG_COPY);
+}
+
+bool RegisterEarlyTraceEvent(JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
+}  // namespace android
+}  // namespace base