Download web payment manifests.

components/payments/android/payment_manifest_downloader_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 "components/payments/android/payment_manifest_downloader_android.h"
+
+#include <memory>
+#include <unordered_map>
+#include <utility>
+
+#include "base/android/jni_string.h"
+#include "base/android/scoped_java_ref.h"
+#include "base/bind.h"
+#include "base/memory/ptr_util.h"
+#include "components/payments/payment_manifest_downloader.h"
+#include "content/public/browser/browser_context.h"
+#include "content/public/browser/storage_partition.h"
+#include "content/public/browser/web_contents.h"
+#include "jni/PaymentManifestDownloader_jni.h"
+#include "net/url_request/url_request_context_getter.h"
+
+namespace payments {
+namespace {
+
+class SelfDeletingDownloadDelegate
+    : public payments::PaymentManifestDownloader::Delegate {
+ public:
+  explicit SelfDeletingDownloadDelegate(
+      const base::android::JavaParamRef<jobject>& jcallback)
+      : jcallback_(jcallback) {}
+
+  void set_downloader(
+      std::unique_ptr<payments::PaymentManifestDownloader> downloader) {
+    downloader_ = std::move(downloader);
+  }
+
+  void Download() { downloader_->Download(); }
+
+  // payments::PaymentManifestDownloader::Delegate
+  void OnManifestDownloadSuccess(const std::string& content) override {
+    JNIEnv* env = base::android::AttachCurrentThread();
+    payments::Java_ManifestDownloadCallback_onManifestDownloadSuccess(
+        env, jcallback_, base::android::ConvertUTF8ToJavaString(env, content));
+    delete this;
+  }
+
+  // payments::PaymentManifestDownloader::Delegate
+  void OnManifestDownloadFailure() override {
+    payments::Java_ManifestDownloadCallback_onManifestDownloadFailure(
+        base::android::AttachCurrentThread(), jcallback_);
+    delete this;
+  }
+
+ private:
+  ~SelfDeletingDownloadDelegate() override {}
+
+  base::android::ScopedJavaGlobalRef<jobject> jcallback_;
+  std::unique_ptr<payments::PaymentManifestDownloader> downloader_;
+
+  DISALLOW_COPY_AND_ASSIGN(SelfDeletingDownloadDelegate);
+};
+
+}  // namespace
+
+void DownloadPaymentManifest(
+    JNIEnv* env,
+    const base::android::JavaParamRef<jclass>& jcaller,
+    const base::android::JavaParamRef<jobject>& jweb_contents,
+    const base::android::JavaParamRef<jstring>& jmethod_name,
+    const base::android::JavaParamRef<jobject>& jcallback) {
+  SelfDeletingDownloadDelegate* delegate =
+      new SelfDeletingDownloadDelegate(jcallback);
+
+  content::WebContents* web_contents =
+      content::WebContents::FromJavaWebContents(jweb_contents);
+  if (!web_contents) {
+    delegate->OnManifestDownloadFailure();
+    return;
+  }
+
+  std::unique_ptr<payments::PaymentManifestDownloader> downloader =
+      base::MakeUnique<payments::PaymentManifestDownloader>(
+          content::BrowserContext::GetDefaultStoragePartition(
+              web_contents->GetBrowserContext())
+              ->GetURLRequestContext(),
+          base::android::ConvertJavaStringToUTF8(env, jmethod_name), delegate);

[palmer, 2017/01/27 00:11:47]

I think here might be a better place to convert the |method_name| string to a
URL? If possible, though, it would be best to declare it as (some kind of) URL
all up and down the Java/native stack. Is it possible? My goal is for bad inputs
to be rejected as early as possible.

[please use gerrit instead, 2017/02/23 19:57:50]

The code now uses a URL all up and down the Java/native stack. The URL parsing
and validation happens in Java as the first step in payment app search.

+  delegate->set_downloader(std::move(downloader));
+  delegate->Download();
+}
+
+}  // namespace payments
+
+bool RegisterPaymentManifestDownloader(JNIEnv* env) {
+  return payments::RegisterNativesImpl(env);
+}