[Chromecast] Turn CastContentWindow into an abstract interface.

chromecast/browser/android/cast_content_window_android.h

+// 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.
+
+#ifndef CHROMECAST_BROWSER_ANDROID_CAST_CONTENT_WINDOW_ANDROID_H_
+#define CHROMECAST_BROWSER_ANDROID_CAST_CONTENT_WINDOW_ANDROID_H_
+
+#include <jni.h>
+
+#include <memory>
+
+#include "base/android/scoped_java_ref.h"
+#include "base/macros.h"
+#include "chromecast/browser/cast_content_window.h"
+#include "content/public/browser/web_contents_observer.h"
+
+namespace content {
+class BrowserContext;
+class WebContents;
+}
+
+namespace chromecast {
+namespace shell {
+
+// Android implementation of CastContentWindow, which displays WebContents in
+// CastWebContentsActivity.
+class CastContentWindowAndroid : public CastContentWindow,
+                                 public content::WebContentsObserver {
+ public:
+  static bool RegisterJni(JNIEnv* env);
+
+  explicit CastContentWindowAndroid(CastContentWindow::Delegate* delegate);

[Wez, 2017/01/11 20:47:54]

As noted in the Linux impl, it doesn't seem that this class needs to be publicly
visible - you can move the definition into the .cc and rely on callers to
Create() it, I think?

[derekjchow1, 2017/01/11 21:54:33]

Your point on constructor visibility is valid, but I think the class definition
should stay visible in it's own header file (at least for the Android case). The
key reason is we need the RegisterJni function to remain public, and I'd rather
keep this function as a static class method to make it obvious what Jni
functions are being registered.

In terms of constructor visibility, I've made the constructor private and added
CastContentWindow as a friend class. This way it can only be constructed via
CastContentWindow::Create. For consistency between platform implementations I've
done the same thing to CastContentWindowLinux.

Does this sound ok?

[Wez, 2017/01/12 21:04:28]

Yes, SGTM - thanks. :)

(If you would prefer to avoid friending, you could instead have a static
Create() directly on this impl class, with an identical signature, that the
generic one simply calls on to.)

+
+  ~CastContentWindowAndroid() override;
+
+  // CastContentWindow implementation:
+  void SetTransparent() override;
+  void ShowWebContents(content::WebContents* web_contents) override;
+  std::unique_ptr<content::WebContents> CreateWebContents(
+      content::BrowserContext* browser_context) override;
+
+  // content::WebContentsObserver implementation:
+  void DidFirstVisuallyNonEmptyPaint() override;
+  void MediaStoppedPlaying(const MediaPlayerInfo& media_info,
+                           const MediaPlayerId& id) override;
+  void MediaStartedPlaying(const MediaPlayerInfo& media_info,
+                           const MediaPlayerId& id) override;
+  void RenderViewCreated(content::RenderViewHost* render_view_host) override;
+
+  // Called through JNI.
+  void OnActivityStopped(JNIEnv* env,
+                         const base::android::JavaParamRef<jobject>& jcaller);
+  void OnKeyDown(JNIEnv* env,
+                 const base::android::JavaParamRef<jobject>& jcaller,
+                 int keycode);
+
+ private:
+  CastContentWindow::Delegate* const delegate_;
+  bool transparent_;
+  base::android::ScopedJavaGlobalRef<jobject> java_window_;
+
+  DISALLOW_COPY_AND_ASSIGN(CastContentWindowAndroid);
+};
+
+}  // namespace shell
+}  // namespace chromecast
+
+#endif  // CHROMECAST_BROWSER_ANDROID_CAST_CONTENT_WINDOW_ANDROID_H_