[Chromecast] Apply exclude_unwind_tables for appropriate builds

This reduces our installed APK size from ~90MB to 65 on ATV.  It
reduces earth OTA size by 1.5MB and earth cast_shell size by 5MB.

Leave unwind tables for builds where we regularly use a debugger (x86
and ATV debug).

BUG=internal b/36082628

Review-Url: https://codereview.chromium.org/2770833003
Cr-Original-Commit-Position: refs/heads/master@{#459619}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: a13b58bb24fb7bc0bbc7d68296ef11a64df4989e

config/compiler/BUILD.gn

@@ -4,6 +4,7 @@
 
 import("//build/config/android/config.gni")
 import("//build/config/chrome_build.gni")
+import("//build/config/chromecast_build.gni")
 import("//build/config/compiler/compiler.gni")
 import("//build/config/nacl/config.gni")
 import("//build/toolchain/cc_wrapper.gni")
@@ -61,7 +62,8 @@ declare_args() {
 
   # Omit unwind support in official builds to save space.
   # We can use breakpad for these builds.
-  exclude_unwind_tables = is_chrome_branded && is_official_build
+  exclude_unwind_tables = (is_chrome_branded && is_official_build) ||
+                          (is_chromecast && !is_cast_desktop_build && !is_debug)
 
   # If true, gold linker will save symbol table inside object files.
   # This speeds up gdb startup by 60%