linux and chromeos: Turn on -Wunused-const-variable.

chrome/app/breakpad_linux.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // For linux_syscall_support.h. This makes it safe to call embedded system
 // calls when in seccomp mode.
 
 #include "chrome/app/breakpad_linux.h"
 
 #include <fcntl.h>
@@ skipping 56 matching lines @@
 // where we either a) know the call cannot fail, or b) there is nothing we
 // can do when a call fails, we mark the return code as ignored. This avoids
 // spurious compiler warnings.
 #define IGNORE_RET(x) do { if (x); } while (0)
 
 using google_breakpad::ExceptionHandler;
 using google_breakpad::MinidumpDescriptor;
 
 namespace {
 
+#if !defined(OS_CHROMEOS)
 const char kUploadURL[] = "https://clients2.google.com/cr/report";
+#endif
 
 bool g_is_crash_reporter_enabled = false;
 uint64_t g_process_start_time = 0;
 char* g_crash_log_path = NULL;
 ExceptionHandler* g_breakpad = NULL;
 
 #if defined(ADDRESS_SANITIZER)
 const char* g_asan_report_str = NULL;
 #endif
 #if defined(OS_ANDROID)
@@ skipping 1414 matching lines @@
     } else {
       EnableNonBrowserCrashDumping(minidump_fd);
     }
   }
 }
 #endif  // OS_ANDROID
 
 bool IsCrashReporterEnabled() {
   return g_is_crash_reporter_enabled;
 }