Add dvlog_always_on to enable DVLOG without DEBUG and DCHECK option

base/BUILD.gn

Index: base/BUILD.gn
diff --git a/base/BUILD.gn b/base/BUILD.gn
index dbd1ff4d1eecd22dd4713770aeba3a82d988b935..361f48e56c060a6b7132a4d0e0c491756b1ed767 100644
--- a/base/BUILD.gn
+++ b/base/BUILD.gn
@@ -24,6 +24,7 @@ import("//build/config/chromecast_build.gni")
 import("//build/config/clang/clang.gni")
 import("//build/config/compiler/compiler.gni")
 import("//build/config/dcheck_always_on.gni")
+import("//build/config/dvlog_always_on.gni")
 import("//build/config/nacl/config.gni")
 import("//build/config/sysroot.gni")
 import("//build/config/ui.gni")
@@ -2773,6 +2774,9 @@ if (is_android) {
     if (is_java_debug || dcheck_always_on) {
       defines += [ "_DCHECK_IS_ON" ]
     }
+    if (is_java_debug || dvlog_always_on) {
+      defines += [ "_DVLOG_IS_ON" ]
+    }
   }
 
   java_cpp_template("base_native_libraries_gen") {