Improve mini installer and official build GN flags

build/config/compiler/BUILD.gn

 # Copyright (c) 2013 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.
 
 import("//build/config/android/config.gni")
 import("//build/config/chrome_build.gni")
 if (current_cpu == "arm") {
   import("//build/config/arm.gni")
 }
 if (current_cpu == "mipsel" || current_cpu == "mips64el") {
@@ skipping 1150 matching lines @@
 #
 #   configs -= default_optimization_config
 #   configs += [ "//build/config/compiler/optimize_max" ]
 
 # Shared settings for both "optimize" and "optimize_max" configs.
 # IMPORTANT: On Windows "/O1" and "/O2" must go before the common flags.
 if (is_win) {
   common_optimize_on_cflags = [
     "/Ob2",  # Both explicit and auto inlining.
     "/Oy-",  # Disable omitting frame pointers, must be after /O2.
+    "/d2Zi+",  # Improve debugging of optimized code.
+    "/Zc:inline",  # Remove unreferenced COMDAT (faster links).
   ]
   if (!is_asan) {
     common_optimize_on_cflags += [
       # Put data in separate COMDATs. This allows the linker
       # to put bit-identical constants at the same address even if
       # they're unrelated constants, which saves binary size.
       # This optimization can't be used when ASan is enabled because
       # it is not compatible with the ASan ODR checker.
       "/Gw",
     ]
   }
-  common_optimize_on_ldflags = [ "/OPT:REF" ]
+  common_optimize_on_ldflags = [ "/OPT:ICF" ]
+  if (is_official_build) {
+    common_optimize_on_ldflags += [
+      # Link-time code generation.
+      "/LTCG",
+
+      # Set the number of LTCG code-gen threads to eight. The default is four.
+      # This gives a 5-10% link speedup.
+      "/cgthreads:8",
+    ]
+  }
 } else {
   common_optimize_on_cflags = [
     # Don't emit the GCC version ident directives, they just end up in the
     # .comment section taking up binary size.
     "-fno-ident",
 
     # Put data and code in their own sections, so that unused symbols
     # can be removed at link time with --gc-sections.
     "-fdata-sections",
     "-ffunction-sections",
@@ skipping 92 matching lines @@
       # that the compile is clean.
       cflags += [
         "/GL",  # Whole program optimization.
 
         # Disable Warning 4702 ("Unreachable code") for the WPO/PGO builds.
         # Probably anything that this would catch that wouldn't be caught in a
         # normal build isn't going to actually be a bug, so the incremental
         # value of C4702 for PGO builds is likely very small.
         "/wd4702",
       ]
-      ldflags += [ "/LTCG" ]
     }
   } else {
     cflags = [ "-O2" ] + common_optimize_on_cflags
   }
 }
 
 # Symbols ----------------------------------------------------------------------
 
 config("symbols") {
   if (is_win) {
@@ skipping 36 matching lines @@
       cflags += [ "-gsplit-dwarf" ]
     }
   }
 }
 
 config("no_symbols") {
   if (!is_win) {
     cflags = [ "-g0" ]
   }
 }