[JJI] Deflake a JsJavaInteractionTest

JsReplyProxy in testJsReplyProxyReplyToTheCorrectJsObject could be null
sometimes, this is because we didn't use ScopedJavaGlobalRef to
reference the corresponding Java object. If a full GC kicked in, the
Java object will be collected, so native side JavaObjectWeakGlobalRef
will return a null.

Bug: 1015023
Change-Id: I66d0f5a9334f98a65e8fd9c05712b5b492a7f788
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1873389Reviewed-by: Richard Coles <torne@chromium.org>
Reviewed-by: Changwan Ryu <changwan@chromium.org>
Commit-Queue: Shimi Zhang <ctzsm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#709150}

android_webview/browser/js_java_interaction/js_reply_proxy.cc

@@ -14,22 +14,20 @@ JsReplyProxy::JsReplyProxy(
         java_to_js_messaging)
     : java_to_js_messaging_(std::move(java_to_js_messaging)) {
   JNIEnv* env = base::android::AttachCurrentThread();
-  java_ref_ = JavaObjectWeakGlobalRef(
-      env, Java_JsReplyProxy_create(env, reinterpret_cast<intptr_t>(this)));
+  java_ref_.Reset(
+      Java_JsReplyProxy_create(env, reinterpret_cast<intptr_t>(this)));
 }
 
 JsReplyProxy::~JsReplyProxy() {
-  JNIEnv* env = base::android::AttachCurrentThread();
-  base::android::ScopedJavaLocalRef<jobject> obj = java_ref_.get(env);
-  if (obj.is_null())
+  if (java_ref_.is_null())
     return;
 
-  Java_JsReplyProxy_onDestroy(env, obj);
+  JNIEnv* env = base::android::AttachCurrentThread();
+  Java_JsReplyProxy_onDestroy(env, java_ref_);
 }
 
 base::android::ScopedJavaLocalRef<jobject> JsReplyProxy::GetJavaPeer() {
-  JNIEnv* env = base::android::AttachCurrentThread();
-  return java_ref_.get(env);
+  return base::android::ScopedJavaLocalRef<jobject>(java_ref_);
 }
 
 void JsReplyProxy::PostMessage(

android_webview/browser/js_java_interaction/js_reply_proxy.h

@@ -26,7 +26,7 @@ class JsReplyProxy {
                    const base::android::JavaParamRef<jstring>& message);
 
  private:
-  JavaObjectWeakGlobalRef java_ref_;
+  base::android::ScopedJavaGlobalRef<jobject> java_ref_;
   mojo::AssociatedRemote<mojom::JavaToJsMessaging> java_to_js_messaging_;
 
   DISALLOW_COPY_AND_ASSIGN(JsReplyProxy);