[chromecast] Removes pepper plugin support.

ppapi/features/features.gni

Index: ppapi/features/features.gni
diff --git a/ppapi/features/features.gni b/ppapi/features/features.gni
index 559373e9794b8f2f4e1ce7acc535f4e656af8b57..5982e3146d0d31149023c086c1801298d263f922 100644
--- a/ppapi/features/features.gni
+++ b/ppapi/features/features.gni
@@ -6,12 +6,11 @@ import("//build/config/chromecast_build.gni")
 import("//build/config/features.gni")
 
 declare_args() {
-  enable_plugins = (!is_android && !is_ios) || is_chromecast
+  enable_plugins = !is_android && !is_ios && !is_chromecast
 }
 
 # Enables the use of CDMs in pepper plugins.
 #
 # This is available as a buildflag for C++ preprocessor, see
 # //ppapi:features.
-enable_pepper_cdms =
-    enable_plugins && (is_linux || is_mac || is_win) && !is_chromecast
+enable_pepper_cdms = enable_plugins && (is_linux || is_mac || is_win)