[Chromecast] Remove dispatchKeyEvent() from CWCA.

This is a less-aggressive version of
https://chromium-review.googlesource.com/c/chromium/src/+/1865756
in case we don't want to nuke everything related to key event
dispatch all at once.

      verify that key events are plumbed to JavaScript.

Bug: Internal b/142758140
Test: cast_shell_junit_tests
Test: cast_shell_unittests
Test: Use chrome://inspect to monitor key events in Cast app to
Change-Id: Ibe312778f74e76b834a80b871eda911adac18cd0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1865146Reviewed-by: Luke Halliwell <halliwell@chromium.org>
Commit-Queue: Simeon Anfinrud <sanfin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#707020}

chromecast/browser/android/apk/src/org/chromium/chromecast/shell/CastWebContentsActivity.java

@@ -235,37 +235,6 @@ public class CastWebContentsActivity extends Activity {
         }
     }
 
-    @Override
-    public boolean dispatchKeyEvent(KeyEvent event) {
-        if (DEBUG) Log.d(TAG, "dispatchKeyEvent");
-        int keyCode = event.getKeyCode();
-        int action = event.getAction();
-
-        // Similar condition for all single-click events.
-        if (action == KeyEvent.ACTION_DOWN && event.getRepeatCount() == 0) {
-            if (keyCode == KeyEvent.KEYCODE_DPAD_CENTER || keyCode == KeyEvent.KEYCODE_DPAD_LEFT
-                    || keyCode == KeyEvent.KEYCODE_MEDIA_REWIND
-                    || keyCode == KeyEvent.KEYCODE_DPAD_RIGHT
-                    || keyCode == KeyEvent.KEYCODE_MEDIA_FAST_FORWARD
-                    || keyCode == KeyEvent.KEYCODE_MEDIA_PLAY_PAUSE
-                    || keyCode == KeyEvent.KEYCODE_MEDIA_PLAY
-                    || keyCode == KeyEvent.KEYCODE_MEDIA_PAUSE
-                    || keyCode == KeyEvent.KEYCODE_MEDIA_STOP
-                    || keyCode == KeyEvent.KEYCODE_MEDIA_NEXT
-                    || keyCode == KeyEvent.KEYCODE_MEDIA_PREVIOUS) {
-                if (mSurfaceHelper != null) {
-                    CastWebContentsComponent.onKeyDown(mSurfaceHelper.getSessionId(), keyCode);
-                }
-                return true;
-            }
-        }
-
-        if (keyCode == KeyEvent.KEYCODE_BACK) {
-            return super.dispatchKeyEvent(event);
-        }
-        return false;
-    }
-
     @Override
     public boolean dispatchGenericMotionEvent(MotionEvent ev) {
         return false;