Reland "Enable libc++ on Android"

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 444 matching lines @@
       if (is_clang) {
         # Let clang find the ld.gold in the NDK.
         ldflags += [ "--gcc-toolchain=" +
                      rebase_path(android_toolchain_root, root_build_dir) ]
       }
     }
 
     ldflags += [
       "-Wl,--no-undefined",
 
-      # Don't allow visible symbols from libgcc or stlport to be
+      # Don't allow visible symbols from libgcc or libc++ to be
       # re-exported.
       "-Wl,--exclude-libs=libgcc.a",
-      "-Wl,--exclude-libs=libstlport_static.a",
+      "-Wl,--exclude-libs=libc++_static.a",
 
       # Don't allow visible symbols from libraries that contain
       # assembly code with symbols that aren't hidden properly.
       # http://crbug.com/448386
       "-Wl,--exclude-libs=libvpx_assembly_arm.a",
     ]
     if (current_cpu == "arm") {
       ldflags += [
         # Enable identical code folding to reduce size.
         "-Wl,--icf=safe",
@@ skipping 61 matching lines @@
   if (is_win) {
     defines += [
       "__STD_C",
       "_CRT_RAND_S",
       "_CRT_SECURE_NO_DEPRECATE",
       "_HAS_EXCEPTIONS=0",
       "_SCL_SECURE_NO_DEPRECATE",
     ]
   }
 
-  # Stlport setup. Android uses a different (smaller) version of the STL.
+  # Android standard library setup.
   if (is_android) {
     if (is_clang) {
       # Work around incompatibilities between bionic and clang headers.
       defines += [
         "__compiler_offsetof=__builtin_offsetof",
         "nan=__builtin_nan",
       ]
     }
 
-    defines += [
-      "USE_STLPORT=1",
-      "_STLP_USE_PTR_SPECIALIZATIONS=1",
-      "__GNU_SOURCE=1",  # Necessary for clone().
-    ]
+    defines += [ "__GNU_SOURCE=1" ]  # Necessary for clone().
 
     # TODO(jdduke) Re-enable on mips after resolving linking
     # issues with libc++ (crbug.com/456380).
     if (current_cpu != "mipsel" && current_cpu != "mips64el") {
       ldflags += [ "-Wl,--warn-shared-textrel" ]
     }
     ldflags += [ "-nostdlib" ]
 
-    # NOTE: The stlport header include paths below are specified in cflags
+    # NOTE: The libc++ header include paths below are specified in cflags
     # rather than include_dirs because they need to come after include_dirs.
     # Think of them like system headers, but don't use '-isystem' because the
     # arm-linux-androideabi-4.4.3 toolchain (circa Gingerbread) will exhibit
     # strange errors. The include ordering here is important; change with
     # caution.
-    android_stlport_root = "$android_ndk_root/sources/cxx-stl/stlport"
+    android_libcpp_root = "$android_ndk_root/sources/cxx-stl/llvm-libc++"
 
-    cflags += [ "-isystem" +
-                rebase_path("$android_stlport_root/stlport", root_build_dir) ]
-    lib_dirs += [ "$android_stlport_root/libs/$android_app_abi" ]
+    cflags += [
+      "-isystem" +
+          rebase_path("$android_libcpp_root/libcxx/include", root_build_dir),
+      "-isystem" + rebase_path(
+              "$android_ndk_root/sources/cxx-stl/llvm-libc++abi/libcxxabi/include",
+              root_build_dir),
+      "-isystem" +
+          rebase_path("$android_ndk_root/sources/android/support/include",
+                      root_build_dir),
+    ]
+
+    lib_dirs += [ "$android_libcpp_root/libs/$android_app_abi" ]
 
     if (component_mode == "shared_library") {
-      libs += [ "stlport_shared" ]
+      android_libcpp_library = "c++_shared"
     } else {
-      libs += [ "stlport_static" ]
-    }
-
-    if (current_cpu == "mipsel") {
-      libs += [
-        # ld linker is used for mips Android, and ld does not accept library
-        # absolute path prefixed by "-l"; Since libgcc does not exist in mips
-        # sysroot the proper library will be linked.
-        # TODO(gordanac): Remove once gold linker is used for mips Android.
-        "gcc",
-      ]
-    } else {
-      libs += [
-        # Manually link the libgcc.a that the cross compiler uses. This is
-        # absolute because the linker will look inside the sysroot if it's not.
-        rebase_path(android_libgcc_file),
-      ]
+      android_libcpp_library = "c++_static"
     }
 
     libs += [
+      "$android_libcpp_library",
+
+      # Manually link the libgcc.a that the cross compiler uses. This is
+      # absolute because the linker will look inside the sysroot if it's not.
+      rebase_path(android_libgcc_file),
       "c",
       "dl",
       "m",
     ]
+
+    # Clang with libc++ does not require an explicit atomic library reference.
+    if (!is_clang) {
+      libs += [ "atomic" ]
+    }
   }
 }
 
 # chromium_code ---------------------------------------------------------------
 #
 # Toggles between higher and lower warnings for code that is (or isn't)
 # part of Chromium.
 
 config("chromium_code") {
   if (is_win) {
@@ skipping 466 matching lines @@
       cflags += [ "-gsplit-dwarf" ]
     }
   }
 }
 
 config("no_symbols") {
   if (!is_win) {
     cflags = [ "-g0" ]
   }
 }