[Chromecast] Add Cast Assistant product type.

Bug: internal b/36447710
Change-Id: I5db3d8203d7c7369a48bff45cbaf582a673c57b6
Review-Url: https://codereview.chromium.org/2786723002
Cr-Commit-Position: refs/heads/master@{#460580}

chromecast/base/BUILD.gn

@@ -12,7 +12,7 @@ if (is_android) {
 
 declare_args() {
   # Denotes the type of Cast product. This is #defined as CAST_PRODUCT_TYPE in
-  # version.h. This is an integer in the range [0-4].
+  # version.h. This is an integer in the range [0-5].
   if (is_android) {
     cast_product_type = 4
   } else {
@@ -23,7 +23,8 @@ declare_args() {
 if (is_android) {
   assert(cast_product_type == 4)
 } else {
-  assert(cast_product_type >= 0 && cast_product_type <= 3)
+  assert(cast_product_type >= 0 && cast_product_type <= 5 &&
+         cast_product_type != 4)
 }
 
 source_set("base") {

components/metrics/proto/cast_logs.proto

@@ -25,6 +25,7 @@ message CastLogsProto {
       CAST_PRODUCT_TYPE_TV = 2;
       CAST_PRODUCT_TYPE_AUDIO = 3;
       CAST_PRODUCT_TYPE_ANDROID_TV = 4;
+      CAST_PRODUCT_TYPE_ASSISTANT = 5;
     }
     optional CastProductType type = 1;