[Chromecast] Don't add icui18n dep for Cast

This dep increases the OTA size by 600kB, which exceeds the size
allowance for debug builds on some devices. Cast likely needs a
different mitigation for Y2038 as a proper long-term fix.

Bug: internal b/167763382
Test: CQ
Change-Id: I71d1834be09e070a6816731b17e0ae8fb7831676
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2399452
Commit-Queue: Sean Topping <seantopping@chromium.org>
Reviewed-by: Peter Kasting <pkasting@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Gabriel Charette <gab@chromium.org>
Reviewed-by: Yuri Wiitala <miu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#814440}

base/BUILD.gn

@@ -1261,6 +1261,7 @@ component("base") {
     "//base/third_party/double_conversion",
     "//base/third_party/dynamic_annotations",
     "//build:branding_buildflags",
+    "//build:chromecast_buildflags",
     "//build:chromeos_buildflags",
     "//third_party/modp_b64",
   ]
@@ -2062,18 +2063,23 @@ component("base") {
   if (is_posix && !is_apple) {
     sources += [
       "time/time_conversion_posix.cc",
-      "time/time_exploded_icu.cc",  # See note below.
       "time/time_exploded_posix.cc",
       "time/time_now_posix.cc",
     ]
 
-    # The ICU dependency is only needed on systems with a 32-bit time_t.
-    # However, that cannot be determined from build variables, like
-    # |current_cpu|, since some 32-bit systems have a 64-bit time_t (and vice
-    # versa). Thus, the dependency is taken here for all POSIX platforms and the
-    # compiler+linker should be able to easily detect when the ICU routines will
-    # not be called and delete them in the final linking.
-    deps += [ "//third_party/icu:icui18n" ]
+    # TODO(b/167763382) Find an alternate solution for Chromecast devices, since
+    # adding the icui18n dep significantly increases the binary size.
+    if (!is_chromecast) {
+      sources += [ "time/time_exploded_icu.cc" ]
+
+      # The ICU dependency is only needed on systems with a 32-bit time_t.
+      # However, that cannot be determined from build variables, like
+      # |current_cpu|, since some 32-bit systems have a 64-bit time_t (and vice
+      # versa). Thus, the dependency is taken here for all POSIX platforms and
+      # the compiler+linker should be able to easily detect when the ICU
+      # routines will not be called and delete them in the final linking.
+      deps += [ "//third_party/icu:icui18n" ]
+    }
   }
 
   if (is_posix && !is_apple && !is_nacl) {

base/time/time_exploded_posix.cc

@@ -18,6 +18,7 @@
 #include "base/numerics/safe_math.h"
 #include "base/synchronization/lock.h"
 #include "build/build_config.h"
+#include "build/chromecast_buildflags.h"
 
 #if defined(OS_NACL)
 #include "base/os_compat_nacl.h"
@@ -126,8 +127,12 @@ void Time::Explode(bool is_local, Exploded* exploded) const {
 
   // For systems with a Y2038 problem, use ICU as the Explode() implementation.
   if (sizeof(SysTime) < 8) {
+// TODO(b/167763382) Find an alternate solution for Chromecast devices, since
+// adding the icui18n dep significantly increases the binary size.
+#if !BUILDFLAG(IS_CHROMECAST)
     ExplodeUsingIcu(millis_since_unix_epoch, is_local, exploded);
     return;
+#endif  // !BUILDFLAG(IS_CHROMECAST)
   }
 
   // Split the |millis_since_unix_epoch| into separate seconds and millisecond