Android: Avoid linking with --gc-sections.

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")
 import("//build/config/compiler/compiler.gni")
 import("//build/config/nacl/config.gni")
 import("//build/toolchain/cc_wrapper.gni")
 import("//build/toolchain/toolchain.gni")
@@ skipping 1350 matching lines @@
   if (is_win) {
     cflags = [
       "/Od",  # Disable optimization.
       "/Ob0",  # Disable all inlining (on by default).
     ]
   } else if (is_android && !android_full_debug) {
     # On Android we kind of optimize some things that don't affect debugging
     # much even when optimization is disabled to get the binary size down.
     cflags = [
       "-Os",
       "-fdata-sections",

[agrieve, 2016/10/03 18:34:17]

Would it make sense to also remove -fdata-sections and -ffunction-sections? I
think these are used only to make --gc-sections work.

[Lei Zhang, 2016/10/03 20:45:50]

Done.

       "-ffunction-sections",
     ]
-
-    # Don't use gc-sections since it can cause links to succeed when they
-    # actually shouldn't. http://crbug.com/159847
-    ldflags = common_optimize_on_ldflags - [ "-Wl,--gc-sections" ]
   } else {
     cflags = [ "-O0" ]
     ldflags = []
   }
 }
 
 # Turns up the optimization level. On Windows, this implies whole program
 # optimization and link-time code generation which is very expensive and should
 # be used sparingly.
 config("optimize_max") {
@@ skipping 200 matching lines @@
 
 if (is_ios || is_mac) {
   # On Mac and iOS, this enables support for ARC (automatic ref-counting).
   # See http://clang.llvm.org/docs/AutomaticReferenceCounting.html.
   config("enable_arc") {
     common_flags = [ "-fobjc-arc" ]
     cflags_objc = common_flags
     cflags_objcc = common_flags
   }
 }