allow unofficial builds with DCHECK and DLOG disabled

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index 23d053034a67ba6bb6eff93af0d697375d076a50..870bca910a9b9b83fb892a79740925d4b41ca0da 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -201,6 +201,12 @@
       # Set to 1 to enable dcheck in release without having to use the flag.
       'dcheck_always_on%': 0,
 
+      # Set to 1 to make a build that logs like an official build, but is not
+      # necessarily an official build, ie DCHECK and DLOG are disabled and
+      # removed completely in release builds, to minimize binary footprint.
+      # Note: this setting is ignored if buildtype=="Official".
+      'logging_like_official_build%': 0,
+
       # Disable file manager component extension by default.
       'file_manager_extension%': 0,
 
@@ -761,6 +767,7 @@
     'image_loader_extension%': '<(image_loader_extension)',
     'fastbuild%': '<(fastbuild)',
     'dcheck_always_on%': '<(dcheck_always_on)',
+    'logging_like_official_build%': '<(logging_like_official_build)',
     'python_ver%': '<(python_ver)',
     'arm_version%': '<(arm_version)',
     'armv7%': '<(armv7)',
@@ -2047,6 +2054,9 @@
       ['dcheck_always_on!=0', {
         'defines': ['DCHECK_ALWAYS_ON=1'],
       }],  # dcheck_always_on!=0
+      ['logging_like_official_build!=0', {
+        'defines': ['LOGGING_IS_OFFICIAL_BUILD=1'],
+      }],  # logging_like_official_build!=0
       ['win_use_allocator_shim==0', {
         'conditions': [
           ['OS=="win"', {