GN: Remove irrelevant targets for Cast Android build

BUILD.gn

Index: BUILD.gn
diff --git a/BUILD.gn b/BUILD.gn
index 3c8b1f5187dc1e0e57e405c905ebd95e01e39fea..ec5e7a3d3503419330c2e0754f9285023e6654ed 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -218,9 +218,6 @@ group("both_gn_and_gyp") {
       "//base/android/linker:chromium_android_linker",
       "//build/android/gyp/test:hello_world",
       "//build/android/rezip",
-      "//chrome/android:chrome_public_apk",
-      "//chrome/android:chrome_public_test_apk",
-      "//chrome/test/chromedriver/test/webview_shell:chromedriver_webview_shell_apk",
       "//third_party/errorprone:chromium_errorprone",
       "//tools/android:android_tools",
       "//tools/imagediff($host_toolchain)",
@@ -306,6 +303,14 @@ group("both_gn_and_gyp") {
       "//url:url_unittests",
     ]
 
+    if (!is_chromecast) {
+      deps += [
+        "//chrome/android:chrome_public_apk",
+        "//chrome/android:chrome_public_test_apk",
+        "//chrome/test/chromedriver/test/webview_shell:chromedriver_webview_shell_apk",
+      ]
+    }
+
     if (has_chrome_android_internal) {
       deps += [ "//clank" ]  # TODO(GYP) ??
     }