[Chromecast] Remove use of VIDEO_HOLE

Removed the switch to re-enable old VIDEO_HOLE path as the overlay
path appears to be working correctly.

BUG=469374

Review URL: https://codereview.chromium.org/1380533002

Cr-Original-Commit-Position: refs/heads/master@{#351571}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: d2b919284b79346539b438641f6a3252dccb113b

common.gypi

@@ -1874,7 +1874,6 @@
             'arm_arch%': '',
             'arm_tune%': 'cortex-a9',
             'arm_thumb%': 1,
-            'video_hole%': 1,
           }],
         ],
       }],

config/features.gni

@@ -89,7 +89,7 @@ declare_args() {
   enable_remoting = !is_ios && !is_android && !is_chromecast
 
   # Enable hole punching for the protected video.
-  enable_video_hole = is_android || is_chromecast
+  enable_video_hole = is_android
 
   # Enables browser side Content Decryption Modules. Required for embedders
   # (e.g. Android and ChromeCast) that use a browser side CDM.