Add Java wrapper for RenderFrameHost

content/browser/frame_host/render_frame_host_android.cc

+// Copyright 2017 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 "content/browser/frame_host/render_frame_host_android.h"
+
+#include "base/android/jni_string.h"
+#include "base/logging.h"
+#include "content/browser/frame_host/render_frame_host_delegate.h"
+#include "content/browser/frame_host/render_frame_host_impl.h"
+#include "jni/RenderFrameHostImpl_jni.h"
+
+using base::android::AttachCurrentThread;
+using base::android::ConvertUTF8ToJavaString;
+using base::android::JavaParamRef;
+using base::android::JavaRef;
+using base::android::ScopedJavaLocalRef;
+
+namespace content {
+
+// static
+bool RenderFrameHostAndroid::Register(JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
+RenderFrameHostAndroid::RenderFrameHostAndroid(
+    RenderFrameHostImpl* render_frame_host)
+    : render_frame_host_(render_frame_host) {
+  JNIEnv* env = AttachCurrentThread();
+  ScopedJavaLocalRef<jobject> obj = Java_RenderFrameHostImpl_create(

[boliu, 2017/03/08 00:39:32]

ahh, missed this earlier..

So right now, there's no strong ref to the java RFH between the constructor here
and GetJavaObject. So in theory, it can be gc-ed between these two calls, so
that GetJavaObject will immediately return null.

Easy fix, lazy create java side in GetJavaObject. Use
JavaObjectWeakGlobalRef::is_uninitialized check instead of actually
dereferencing weakref though.

[do_not_use, 2017/03/08 18:28:27]

Done, hope I did it correctly.

+      env, reinterpret_cast<intptr_t>(this),
+      render_frame_host->delegate()->GetJavaRenderFrameHostDelegate());
+  obj_ = JavaObjectWeakGlobalRef(env, obj);
+}
+
+RenderFrameHostAndroid::~RenderFrameHostAndroid() {
+  ScopedJavaLocalRef<jobject> jobj = GetJavaObject();
+  if (!jobj.is_null()) {
+    Java_RenderFrameHostImpl_clearNativePtr(AttachCurrentThread(), jobj);
+    obj_.reset();
+  }
+}
+
+base::android::ScopedJavaLocalRef<jobject>
+RenderFrameHostAndroid::GetJavaObject() {
+  JNIEnv* env = base::android::AttachCurrentThread();
+  return obj_.get(env);
+}
+
+ScopedJavaLocalRef<jstring> RenderFrameHostAndroid::GetLastCommittedURL(
+    JNIEnv* env,
+    const JavaParamRef<jobject>& obj) const {
+  return ConvertUTF8ToJavaString(
+      env, render_frame_host_->GetLastCommittedURL().spec());
+}
+
+}  // namespace content