Link MediaSessionTabHelper with native MediaSession [CL is going to be split]

content/public/android/java/src/org/chromium/content/browser/webcontents/WebContentsObserverProxy.java

Index: content/public/android/java/src/org/chromium/content/browser/webcontents/WebContentsObserverProxy.java
diff --git a/content/public/android/java/src/org/chromium/content/browser/webcontents/WebContentsObserverProxy.java b/content/public/android/java/src/org/chromium/content/browser/webcontents/WebContentsObserverProxy.java
index 365811066e556c685eed2f61288dc6209780f153..2efff194b7f1bd89cddeec2561591acd650a6477 100644
--- a/content/public/android/java/src/org/chromium/content/browser/webcontents/WebContentsObserverProxy.java
+++ b/content/public/android/java/src/org/chromium/content/browser/webcontents/WebContentsObserverProxy.java
@@ -11,7 +11,6 @@ import org.chromium.base.VisibleForTesting;
 import org.chromium.base.annotations.CalledByNative;
 import org.chromium.base.annotations.JNINamespace;
 import org.chromium.content_public.browser.WebContentsObserver;
-import org.chromium.content_public.common.MediaMetadata;
 
 /**
  * Serves as a compound observer proxy for dispatching WebContentsObserver callbacks,
@@ -248,22 +247,6 @@ class WebContentsObserverProxy extends WebContentsObserver {
 
     @Override
     @CalledByNative
-    public void mediaSessionStateChanged(boolean isControllable, boolean isSuspended) {
-        for (mObserversIterator.rewind(); mObserversIterator.hasNext();) {
-            mObserversIterator.next().mediaSessionStateChanged(isControllable, isSuspended);
-        }
-    }
-
-    @Override
-    @CalledByNative
-    public void mediaSessionMetadataChanged(MediaMetadata metadata) {
-        for (mObserversIterator.rewind(); mObserversIterator.hasNext();) {
-            mObserversIterator.next().mediaSessionMetadataChanged(metadata);
-        }
-    }
-
-    @Override
-    @CalledByNative
     public void destroy() {
         // Super destruction semantics (removing the observer from the
         // Java-based WebContents) are quite different, so we explicitly avoid