[build] Add build options for uftrace support

BUILD.gn

 # Copyright 2014 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/arm.gni")
 import("//build/config/dcheck_always_on.gni")
 import("//build/config/mips.gni")
 import("//build/config/sanitizers/sanitizers.gni")
 
@@ skipping 51 matching lines @@
   v8_no_inline = false
 
   # Override OS page size when generating snapshot
   v8_os_page_size = "0"
 
   # Similar to vfp but on MIPS.
   v8_can_use_fpu_instructions = true
 
   # Similar to the ARM hard float ABI but on MIPS.
   v8_use_mips_abi_hardfloat = true
+
+  # Build with -pg option for gprof or uftrace
+  v8_pg_build = false
+
+  # Build with -finstrument-functions option for uftrace or general function
+  # instrumentation
+  v8_finstrument_build = false
 }
 
 # Set project-specific defaults for some args if not provided in args.gn. The
 # defaults can be set in the respective build_overrides files.
 if (v8_imminent_deprecation_warnings == "") {
   if (defined(v8_imminent_deprecation_warnings_default)) {
     v8_imminent_deprecation_warnings = v8_imminent_deprecation_warnings_default
   } else {
     v8_imminent_deprecation_warnings = false
   }
@@ skipping 282 matching lines @@
     defines += [ "DEBUG" ]
   }
 
   if (v8_no_inline) {
     cflags += [
       "-fno-inline-functions",
       "-fno-inline",
     ]
   }
 
+  if (v8_pg_build) {
+    cflags += [
+      "-pg",
+      "-fno-omit-frame-pointer",
+    ]
+  }
+
+  if (v8_finstrument_build) {
+    cflags += [
+      "-finstrument-functions",
+      "-fno-omit-frame-pointer",
+    ]
+  }
+
   if (is_clang) {
     cflags += [
       "-Wsign-compare",
 
       # TODO(hans): Remove once http://crbug.com/428099 is resolved.
       "-Winconsistent-missing-override",
     ]
 
     if (v8_current_cpu == "x64" || v8_current_cpu == "arm64" ||
         v8_current_cpu == "mips64el") {
@@ skipping 2613 matching lines @@
   ]
 
   configs = [
     ":external_config",
     ":internal_config_base",
   ]
 }
 
 v8_fuzzer("wasm_data_section_fuzzer") {
 }