Changes to support Android Things N on Cast master

Test: Built and Run with Android N(on Cast Master) changes (Cast + setup) on the AT1
Bug: 118437285
Change-Id: Iff72a2a2d8eabda619940a256bab1b23daf00c26
Reviewed-on: https://chromium-review.googlesource.com/c/1331579
Commit-Queue: Elvin L <elvin@chromium.org>
Reviewed-by: Luke Halliwell <halliwell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#608393}

chromecast/BUILD.gn

@@ -589,6 +589,7 @@ buildflag_header("chromecast_buildflags") {
     "SUPPORTS_MULTIZONE=$supports_multizone",
     "USE_ANDROID_USER_AGENT=$use_android_user_agent",
     "USE_CHROMECAST_CDMS=$use_chromecast_cdms",
+    "USE_ANDROID_THINGS_N=$build_for_android_things_n",
   ]
 }
 

chromecast/base/BUILD.gn

@@ -199,8 +199,7 @@ cast_source_set("cast_sys_info") {
       "cast_sys_info_android.h",
       "cast_sys_info_android_factory.cc",
     ]
-
-    if (is_android_things) {
+    if (is_android_things && !build_for_android_things_n) {
       sources += [
         "cast_sys_info_android_things.cc",
         "cast_sys_info_android_things.h",

chromecast/base/cast_sys_info_android_factory.cc

@@ -12,7 +12,8 @@ namespace chromecast {
 
 // static
 std::unique_ptr<CastSysInfo> CreateSysInfo() {
-#if BUILDFLAG(IS_ANDROID_THINGS)
+// Not used for Android N because N doesn't support ro.oem.*
+#if BUILDFLAG(IS_ANDROID_THINGS) && !BUILDFLAG(USE_ANDROID_THINGS_N)
   return std::make_unique<CastSysInfoAndroidThings>();
 #else
   return std::make_unique<CastSysInfoAndroid>();

chromecast/browser/BUILD.gn

@@ -537,7 +537,7 @@ if (is_android) {
       "android/apk/src/org/chromium/chromecast/shell/CastSysInfoAndroid.java",
     ]
 
-    if (is_android_things_non_public) {
+    if (is_android_things_non_public && !build_for_android_things_n) {
       sources += [ "android/apk/src/org/chromium/chromecast/shell/CastSysInfoAndroidThings.java" ]
     }
 

chromecast/browser/android/BUILD.gn

@@ -154,7 +154,7 @@ android_library("cast_shell_java") {
     deps += [ "//chromecast/media/cma/backend/android:audio_track_java" ]
   }
 
-  if (is_android_things_non_public) {
+  if (is_android_things_non_public && !build_for_android_things_n) {
     java_files += [ "$java_src_dir/org/chromium/chromecast/shell/CastSysInfoAndroidThings.java" ]
     deps += [ "//chromecast/internal/android/prebuilt/things:support_lib_java" ]
     if (enable_assistant) {

chromecast/chromecast.gni

@@ -101,6 +101,9 @@ declare_args() {
 
   # Set to true to enable wayland server
   enable_cast_wayland_server = false
+
+  # Whether to build cast for Android Things N version
+  build_for_android_things_n = false
 }
 
 declare_args() {

chromecast/media/cma/backend/android/java/src/org/chromium/chromecast/cma/backend/android/VolumeMap.java

@@ -82,7 +82,8 @@ public final class VolumeMap {
     // Returns the current volume in dB for the given stream type and volume index.
     private static float getStreamVolumeDB(int streamType, int idx) {
         float db = 0;
-        if (Build.VERSION.SDK_INT == Build.VERSION_CODES.O_MR1) {
+        if (Build.VERSION.SDK_INT == Build.VERSION_CODES.O_MR1
+                || Build.VERSION.SDK_INT == Build.VERSION_CODES.N) {
             // API is hidden, use reflection.
             try {
                 db = (float) getAudioManager()