Refactor ShortcutHelper (Java/C++) to allow asynchronous init.

chrome/browser/android/shortcut_helper.h

 // Copyright 2013 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.
 
 #ifndef CHROME_BROWSER_ANDROID_SHORTCUT_HELPER_H_
 #define CHROME_BROWSER_ANDROID_SHORTCUT_HELPER_H_
 
+#include "base/android/jni_android.h"
 #include "base/android/jni_weak_ref.h"
 #include "base/basictypes.h"
 #include "base/strings/string16.h"
 #include "base/task/cancelable_task_tracker.h"
-#include "chrome/browser/android/tab_android.h"
+#include "components/favicon_base/favicon_types.h"
 #include "content/public/browser/web_contents_observer.h"
 
-namespace favicon_base {
-struct FaviconRawBitmapResult;
-}  // namespace favicon_base
-
 namespace content {
 class WebContents;
 }  // namespace content
 
 namespace IPC {
 class Message;
 }
 
 class GURL;
 
-// Adds a shortcut to the current URL to the Android home screen.
-// This proceeds over three phases:
-// 1) The renderer is asked to parse out webapp related meta tags with an async
-//    IPC message.
-// 2) The highest-resolution favicon available is retrieved for use as the
-//    icon on the home screen.
-// 3) A JNI call is made to fire an Intent at the Android launcher, which adds
-//    the shortcut.
-class ShortcutBuilder : public content::WebContentsObserver {
+// ShortcutHelper is the C++ counterpart of org.chromium.chrome.browser's
+// ShortcutHelper in Java. The object is owned by the Java object. It is created
+// from there via a JNI (Initialize) call and can be destroyed from Java too
+// using TearDown. When the Java implementations calls AddShortcut, it gives up
+// the ownership of the object. The instance will then destroy itself when done.
+class ShortcutHelper : public content::WebContentsObserver {
  public:
   enum ShortcutType {
     APP_SHORTCUT,
     APP_SHORTCUT_APPLE,
     BOOKMARK
   };
 
-  explicit ShortcutBuilder(content::WebContents* web_contents,
-                           const base::string16& title,
-                           int launcher_large_icon_size);
-  virtual ~ShortcutBuilder() {}
+  explicit ShortcutHelper(JNIEnv* env,

[Bernhard Bauer, 2014/09/12 11:30:48]

Explicit is only necessary for single-argument constructors.

[mlamouri (slow - plz ping), 2014/09/12 11:48:43]

Fixed. It used to be one argument. Forgot to update.

+                          jobject obj,
+                          content::WebContents* web_contents);
 
+  // Initialize the helper by requesting the information about the page to the
+  // renderer process. The initialization is asynchronous and
+  // OnDidRetrieveWebappInformation is expected to be called when finished.
+  void Initialize();
+
+  // Called by the Java counter part to let the object knows that it can destroy
+  // itself.
+  void TearDown(JNIEnv* env, jobject obj);
+
+  // IPC message received when the initialization is finished.
   void OnDidRetrieveWebappInformation(bool success,
                                       bool is_mobile_webapp_capable,
                                       bool is_apple_mobile_webapp_capable,
                                       const GURL& expected_url);
 
+  // Adds a shortcut to the current URL to the Android home screen.
+  void AddShortcut(JNIEnv* env,
+                   jobject obj,
+                   jstring title,
+                   jint launcher_large_icon_size);
+
   void FinishAddingShortcut(
       const favicon_base::FaviconRawBitmapResult& bitmap_result);
 
   // WebContentsObserver
   virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
   virtual void WebContentsDestroyed() OVERRIDE;
 
- private:
-  void Destroy();
-
-  GURL url_;
-  base::string16 title_;
-  int launcher_large_icon_size_;
-  ShortcutType shortcut_type_;
-  base::CancelableTaskTracker cancelable_task_tracker_;
-
-  DISALLOW_COPY_AND_ASSIGN(ShortcutBuilder);
-};
-
-class ShortcutHelper {
- public:
-  // Adds a shortcut to the current URL to the Android home screen, firing
-  // background tasks to pull all the data required.
-  static void AddShortcut(content::WebContents* web_contents,
-                          const base::string16& title,
-                          int launcher_larger_icon_size);
-
   // Adds a shortcut to the launcher.  Must be called from a WorkerPool task.
   static void AddShortcutInBackground(
       const GURL& url,
       const base::string16& title,
-      ShortcutBuilder::ShortcutType shortcut_type,
+      ShortcutType shortcut_type,
       const favicon_base::FaviconRawBitmapResult& bitmap_result);
 
   // Registers JNI hooks.
   static bool RegisterShortcutHelper(JNIEnv* env);
 
  private:
+  virtual ~ShortcutHelper();
+
+  void Destroy();
+
+  JavaObjectWeakGlobalRef java_ref_;
+
+  GURL url_;
+  base::string16 title_;
+  int launcher_large_icon_size_;
+  ShortcutType shortcut_type_;
+  favicon_base::FaviconRawBitmapResult icon_;
+  base::CancelableTaskTracker cancelable_task_tracker_;
+
   DISALLOW_COPY_AND_ASSIGN(ShortcutHelper);
 };
 
 #endif  // CHROME_BROWSER_ANDROID_SHORTCUT_HELPER_H_