Add MemoryStateListenerAndroid

components/memory_coordinator/android/memory_state_listener_android.cc

Index: components/memory_coordinator/android/memory_state_listener_android.cc
diff --git a/components/memory_coordinator/android/memory_state_listener_android.cc b/components/memory_coordinator/android/memory_state_listener_android.cc
new file mode 100644
index 0000000000000000000000000000000000000000..0ea15b06aaacfdd69dfe360fc6c7bf32c052cdd3
--- /dev/null
+++ b/components/memory_coordinator/android/memory_state_listener_android.cc
@@ -0,0 +1,71 @@
+// 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 "components/memory_coordinator/android/memory_state_listener_android.h"
+
+#include "base/android/context_utils.h"
+#include "base/android/jni_android.h"
+#include "base/lazy_instance.h"
+#include "base/synchronization/lock.h"
+#include "jni/MemoryStateListener_jni.h"
+
+namespace memory_coordinator {
+
+namespace {
+
+base::LazyInstance<base::Lock>::Leaky g_lock = LAZY_INSTANCE_INITIALIZER;
+MemoryStateListenerAndroidDelegate* g_delegate = nullptr;
+
+}  // namespace
+
+// Declared by jni_generator and called by JNI.
+static void OnTrimMemory(JNIEnv* env,
+                         const base::android::JavaParamRef<jclass>& jcaller,
+                         jint level) {
+  base::AutoLock lock(*g_lock.Pointer());
+  if (g_delegate) {
+    g_delegate->OnTrimMemory(level);
+  }
+}
+
+// static
+bool MemoryStateListenerAndroid::Register(JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
+// static
+void MemoryStateListenerAndroid::Start(
+    MemoryStateListenerAndroidDelegate* delegate) {
+  base::AutoLock lock(*g_lock.Pointer());
+  DCHECK(!g_delegate);
+  g_delegate = delegate;
+  Java_MemoryStateListener_registerCallback(
+      base::android::AttachCurrentThread(),
+      base::android::GetApplicationContext());
+}
+
+// static
+void MemoryStateListenerAndroid::Stop() {
+  base::AutoLock lock(*g_lock.Pointer());
+  DCHECK(g_delegate);
+  Java_MemoryStateListener_unregisterCallback(
+      base::android::AttachCurrentThread(),
+      base::android::GetApplicationContext());
+  g_delegate = nullptr;
+}
+
+// static
+void MemoryStateListenerAndroid::SimulateOnTrimMemory(int level) {
+  JNIEnv* env = base::android::AttachCurrentThread();
+  base::android::ScopedJavaLocalRef<jclass> application_clazz =
+      base::android::GetClass(env, "android/app/Application");
+  jmethodID method =
+      base::android::MethodID::Get<base::android::MethodID::TYPE_INSTANCE>(
+          env, application_clazz.obj(), "onTrimMemory", "(I)V");
+  const base::android::JavaRef<jobject>& context =
+      base::android::GetApplicationContext();
+  env->CallVoidMethod(context.obj(), method, level);
+}
+
+}  // namespace memory_coordinator