Revert "[Chromecast] Add API to set and clear image on video plane"

Removing cast.__platform__.vidoePlane bindings.
This reverts commit 1f4c122

Bug: internal b/119639315
Test: CQ
Change-Id: I188445d84b02b120408f357280d84311810b777c
Reviewed-on: https://chromium-review.googlesource.com/c/1387729
Reviewed-by: Luke Halliwell <halliwell@chromium.org>
Commit-Queue: Marzena Dell'Aquila <mdellaquila@google.com>
Cr-Commit-Position: refs/heads/master@{#619830}

chromecast/public/cast_media_shlib.h

@@ -140,13 +140,6 @@ class CHROMECAST_EXPORT CastMediaShlib {
                                      const std::string& config)
       __attribute__((__weak__));
 
-  // Only used on Chromecast: set and clear an image on the video plane.
-  // Image data is 8-bit ARGB format; |data| buffer byte length must be
-  // |width|*|height|*4. Returns whether the image could be successfully set.
-  static bool SetVideoPlaneImage(int width, int height, const uint8_t* data)
-      __attribute__((__weak__));
-  static void ClearVideoPlaneImage() __attribute__((__weak__));
-
   // Sets up a direct audio source for output. The media backend will pull audio
   // directly from |source| whenever more output data is needed; this provides
   // low-latency output. The source must remain valid until