Introduce ManifestUpgradeDetector for WebAPK to detect web manifest changes.

chrome/browser/android/webapk/manifest_upgrade_detector.cc

Index: chrome/browser/android/webapk/manifest_upgrade_detector.cc
diff --git a/chrome/browser/android/webapk/manifest_upgrade_detector.cc b/chrome/browser/android/webapk/manifest_upgrade_detector.cc
new file mode 100644
index 0000000000000000000000000000000000000000..96203569fabdfef5eb8a97eda518423b63349e00
--- /dev/null
+++ b/chrome/browser/android/webapk/manifest_upgrade_detector.cc
@@ -0,0 +1,145 @@
+// 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 "chrome/browser/android/webapk/manifest_upgrade_detector.h"
+
+#include <jni.h>
+
+#include "base/android/jni_string.h"
+#include "chrome/browser/android/shortcut_info.h"
+#include "content/public/browser/render_frame_host.h"
+#include "content/public/browser/web_contents.h"
+#include "content/public/common/manifest.h"
+#include "jni/ManifestUpgradeDetector_jni.h"
+#include "url/gurl.h"
+
+namespace {
+
+// Returns whether the given |url| is within the scope of the |scope| url.
+bool IsInScope(const GURL& url, const GURL& scope) {
+  return base::StartsWith(url.spec(), scope.spec(),
+                         base::CompareCase::SENSITIVE);
+}
+
+}  // anonymous namespace
+
+jlong Initialize(JNIEnv* env,
+                 const JavaParamRef<jobject>& obj,
+                 const JavaParamRef<jobject>& java_web_contents,
+                 const JavaParamRef<jstring>& java_scope_url,
+                 const JavaParamRef<jstring>& java_web_manifest_url) {
+  content::WebContents* web_contents =
+      content::WebContents::FromJavaWebContents(java_web_contents);
+  GURL scope(base::android::ConvertJavaStringToUTF8(env, java_scope_url));
+  GURL web_manifest_url(base::android::ConvertJavaStringToUTF8(
+      env, java_web_manifest_url));
+  ManifestUpgradeDetector* manifest_upgrade_detector =
+      new ManifestUpgradeDetector(env, obj, web_contents, scope,
+                                  web_manifest_url);
+  return reinterpret_cast<intptr_t>(manifest_upgrade_detector);
+}
+
+ManifestUpgradeDetector::ManifestUpgradeDetector(
+    JNIEnv* env,
+    jobject obj,
+    content::WebContents* web_contents,
+    const GURL& scope,
+    const GURL& web_manifest_url)
+    : content::WebContentsObserver(web_contents),
+      started_(false),
+      scope_(scope),
+      web_manifest_url_(web_manifest_url),
+      error_code_(NoErrorDetected),
+      weak_ptr_factory_(this) {
+  java_ref_.Reset(env, obj);
+}
+
+ManifestUpgradeDetector::~ManifestUpgradeDetector() {
+}
+
+// static
+bool ManifestUpgradeDetector::Register(JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
+void ManifestUpgradeDetector::ReplaceWebContents(
+    JNIEnv* env,
+    const JavaParamRef<jobject>& obj,
+    const JavaParamRef<jobject>& jweb_contents) {
+  content::WebContents* web_contents =
+      content::WebContents::FromJavaWebContents(jweb_contents);
+  content::WebContentsObserver::Observe(web_contents);
+}
+
+void ManifestUpgradeDetector::Destroy(JNIEnv* env,
+                                      const JavaParamRef<jobject>& obj) {
+  delete this;
+}
+
+void ManifestUpgradeDetector::Start(JNIEnv* env,
+                                    const JavaParamRef<jobject>& obj) {
+  started_ = true;
+}
+
+void ManifestUpgradeDetector::DidFinishLoad(
+    content::RenderFrameHost* render_frame_host,
+    const GURL& validated_url) {
+  if (render_frame_host->GetParent())
+    return;
+  if (!started_ || !IsInScope(validated_url, scope_))
+    return;
+
+  web_contents()->GetManifest(
+      base::Bind(&ManifestUpgradeDetector::OnDidGetManifest,
+                 weak_ptr_factory_.GetWeakPtr()));
+}
+
+void ManifestUpgradeDetector::OnDidGetManifest(
+    const GURL& manifest_url,
+    const content::Manifest& manifest) {
+  // If the manifest is empty, it means the current WebContents doesn't
+  // associate with a Web Manifest. In such case, we ignore the empty manifest
+  // and continue observing the WebContents's loading until we find a page that
+  // links to the Web Manifest that we are looking for.
+  // If the manifest URL is different from the current one, we will continue
+  // observing too. It is based on our assumption that it is invalid for
+  // web developers to change the Web Manifest location. When it does
+  // change, we will treat the new Web Manifest as the one of another WebAPK.

[pkotwicz, 2016/07/25 17:35:53]

Yaron do you have a good comment to put here to explain why we early return when
|web_manifest_url_| != manifest_url

[Yaron, 2016/07/25 18:00:21]

I think Xi's comment is correct. As currently planned, when you install a
WebApk, it will not follow you if the manifest url changes. But we have to
reflect the fact that the old WebApk was launched for the previous manifest url
and we wait to see if the user discovers a new version of it.

Actually if it doesn't match, it really shouldn't return FetchedManifestEmpty -
it's a no-op.

[Xi Han, 2016/07/25 20:01:38]

Good catch, the FetchedManifestEmpty is only covered the case of
manifest.IsEmpty():(

+  if (manifest.IsEmpty() || web_manifest_url_ != manifest_url) {
+    error_code_ = FetchedManifestEmpty;
+    return;
+  }
+
+  started_ = false;
+
+  ShortcutInfo info(GURL::EmptyGURL());
+  info.UpdateFromManifest(manifest);
+  info.manifest_url = manifest_url;
+
+  OnDataAvailable(info);
+}
+
+void ManifestUpgradeDetector::OnDataAvailable(const ShortcutInfo& info) {
+  JNIEnv* env = base::android::AttachCurrentThread();
+
+  ScopedJavaLocalRef<jstring> java_url =
+      base::android::ConvertUTF8ToJavaString(env, info.url.spec());
+  ScopedJavaLocalRef<jstring> java_scope =
+      base::android::ConvertUTF8ToJavaString(env, info.scope.spec());
+  ScopedJavaLocalRef<jstring> java_name =
+      base::android::ConvertUTF16ToJavaString(env, info.name);
+  ScopedJavaLocalRef<jstring> java_short_name =
+      base::android::ConvertUTF16ToJavaString(env, info.short_name);
+
+  Java_ManifestUpgradeDetector_onDataAvailable(
+      env, java_ref_.obj(),
+      java_url.obj(),
+      java_scope.obj(),
+      java_name.obj(),
+      java_short_name.obj(),
+      info.display,
+      info.orientation,
+      info.theme_color,
+      info.background_color);
+}