[Android] A prototype of the interactive media notification.

chrome/browser/android/chrome_web_contents_delegate_android.cc

Index: chrome/browser/android/chrome_web_contents_delegate_android.cc
diff --git a/chrome/browser/android/chrome_web_contents_delegate_android.cc b/chrome/browser/android/chrome_web_contents_delegate_android.cc
index 7867ae17c1060cff6fe50d4955f6674dbd051156..a7a25ab010d92101a9ccd686d9afdcfab61decb9 100644
--- a/chrome/browser/android/chrome_web_contents_delegate_android.cc
+++ b/chrome/browser/android/chrome_web_contents_delegate_android.cc
@@ -24,6 +24,7 @@
 #include "chrome/browser/ui/tab_helpers.h"
 #include "chrome/common/chrome_switches.h"
 #include "components/app_modal/javascript_dialog_manager.h"
+#include "content/public/browser/android/media_controls_delegate.h"
 #include "content/public/browser/notification_details.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/notification_source.h"
@@ -352,6 +353,35 @@ void ChromeWebContentsDelegateAndroid::AddNewContents(
     delete new_contents;
 }
 
+
+void ChromeWebContentsDelegateAndroid::ShowMediaControls(
+    WebContents* web_contents) {
+  DCHECK(web_contents);
+
+  JNIEnv* env = AttachCurrentThread();
+  ScopedJavaLocalRef<jobject> obj = GetJavaDelegate(env);
+  if (obj.is_null())
+    return;
+
+  content::MediaControlsDelegate* delegate =
+      web_contents->GetMediaControlsDelegate();
+  jboolean jis_paused = delegate->IsPaused();

[mlamouri (slow - plz ping), 2015/06/18 16:43:22]

If I understand correctly, the only reason why you have this IsPaused() call is
because you will call ShowMediaControls() to signal that there is a play/pause
state change, right? It seems that we could generalize that behaviour by having
simply a UpdateMediaControls() and have the method check with the
MediaControlsDelegate what should be done. Alternatively, we could have an
object hanging from WebContentsDelegate that would represent the Media Controls
so the MediaSession could directly tell it to Show(), Hide(), Update(), etc.

[whywhat, 2015/06/19 16:00:34]

So why would you want to split Show and Update?
This method currently does exactly what you describe as the first option. For
the alternative, WebContentsDelegate works like that object now with
MediaSession calling it directly when it needs to show/hide the notification.

I'd like to minimize cross components and Java/C++ interface so would like to
avoid Show/UpdateTitle/UpdateState/UpdateIcon/Hide style interface.

[mlamouri (slow - plz ping), 2015/06/22 14:34:17]

What would you think of having UpdateMediaControls() then have the
WebContentsDelegate use the MediaControlsDelegate to check whether the controls
should be paused, shown, etc. It might be a better signal if we want later to
update the title, etc. Instead of Show/Hide and Show being used for updates too,
we have one Update signal. WDYT?

[whywhat, 2015/06/23 19:39:10]

Per offline discussion we agreed that there're two distinct use cases:
- when media session changes its active state (so that the embedder could
start/stop listening to media keys, setup/tear down the lock screen and software
keys via the notification, etc)
- when something relevant to the visible ui changes, e.g. title, icon, playback
state, etc

I think we could have a single method still to notify of any state change and
the delegate would then determine what changed and do the appropriate action.

+  Java_ChromeWebContentsDelegateAndroid_showMediaControls(
+      env, obj.obj(), jis_paused);
+}
+
+void ChromeWebContentsDelegateAndroid::HideMediaControls(
+    WebContents* web_contents) {
+  DCHECK(web_contents);
+
+  JNIEnv* env = AttachCurrentThread();
+  ScopedJavaLocalRef<jobject> obj = GetJavaDelegate(env);
+  if (obj.is_null())
+    return;
+
+  Java_ChromeWebContentsDelegateAndroid_hideMediaControls(env, obj.obj());
+}
+
 }  // namespace android
 }  // namespace chrome
 
@@ -384,3 +414,23 @@ jboolean HasAudibleAudio(JNIEnv* env,
       content::WebContents::FromJavaWebContents(java_web_contents);
   return web_contents->WasRecentlyAudible();
 }
+
+void OnMediaControlsPause(
+    JNIEnv* env, jclass clazz, jobject java_web_contents) {
+  content::WebContents* web_contents =
+      content::WebContents::FromJavaWebContents(java_web_contents);
+  content::MediaControlsDelegate* delegate =
+      web_contents->GetMediaControlsDelegate();
+  if (delegate)
+    delegate->OnControlsPause();
+}
+
+void OnMediaControlsResume(
+    JNIEnv* env, jclass clazz, jobject java_web_contents) {
+  content::WebContents* web_contents =
+      content::WebContents::FromJavaWebContents(java_web_contents);
+  content::MediaControlsDelegate* delegate =
+      web_contents->GetMediaControlsDelegate();
+  if (delegate)
+    delegate->OnControlsResume();
+}