Desktop Chrome OS: Build with precise sysroot (Reland)

build/config/sysroot.gni

 # 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.
 
 # This header file defines the "sysroot" variable which is the absolute path
 # of the sysroot. If no sysroot applies, the variable will be an empty string.
 
 import("//build/config/chrome_build.gni")
 
 declare_args() {
@@ skipping 26 matching lines @@
     sysroot = "$android_ndk_root/$mips_android_sysroot_subdir"
   } else if (current_cpu == "x64") {
     sysroot = "$android_ndk_root/$x86_64_android_sysroot_subdir"
   } else if (current_cpu == "arm64") {
     sysroot = "$android_ndk_root/$arm64_android_sysroot_subdir"
   } else if (current_cpu == "mips64el") {
     sysroot = "$android_ndk_root/$mips64_android_sysroot_subdir"
   } else {
     sysroot = ""
   }
-} else if (is_linux && !is_chromeos && use_sysroot) {
+} else if (is_linux && use_sysroot) {
   # By default build against a sysroot image downloaded from Cloud Storage
   # during gclient runhooks.
-  if (current_cpu == "x64") {
-    sysroot = "//build/linux/debian_wheezy_amd64-sysroot"
-  } else if (current_cpu == "x86") {
-    sysroot = "//build/linux/debian_wheezy_i386-sysroot"
-  } else if (current_cpu == "mipsel") {
-    sysroot = "//build/linux/debian_wheezy_mips-sysroot"
-  } else if (current_cpu == "arm") {
-    sysroot = "//build/linux/debian_wheezy_arm-sysroot"
-  } else if (current_cpu == "arm64") {
-    sysroot = "//build/linux/debian_jessie_arm64-sysroot"
+  if (is_chromeos) {
+    # Regular ChromeOS builds use custom sysroots, but desktop ChromeOS (where
+    # we're building linux desktop binaries but using the ChromeOS UI and
+    # functionality where possible) needs to run on the buliders, which are
+    # running precise.  The precise build has a different set of dependencies
+    # from the wheezy build, so we cannot use the wheezy sysroot.
+    sysroot = "//build/linux/ubuntu_precise_amd64-sysroot"
   } else {
-    # Any other builds don't use a sysroot.
-    sysroot = ""
+    if (current_cpu == "x64") {
+      sysroot = "//build/linux/debian_wheezy_amd64-sysroot"
+    } else if (current_cpu == "x86") {
+      sysroot = "//build/linux/debian_wheezy_i386-sysroot"
+    } else if (current_cpu == "mipsel") {
+      sysroot = "//build/linux/debian_wheezy_mips-sysroot"
+    } else if (current_cpu == "arm") {
+      sysroot = "//build/linux/debian_wheezy_arm-sysroot"
+    } else if (current_cpu == "arm64") {
+      sysroot = "//build/linux/debian_jessie_arm64-sysroot"
+    } else {
+      # Any other builds don't use a sysroot.
+      sysroot = ""
+    }
   }
 
   if (sysroot != "") {
     # Our sysroot images only contains gcc 4.6 headers, but chromium requires
     # gcc 4.9. Clang is able to detect and work with the 4.6 headers while
     # gcc is not. This check can be removed if we ever update to a more modern
     # sysroot.
     assert(is_clang, "sysroot images require clang (try use_sysroot=false)")
 
     _script_arch = current_cpu
@@ skipping 10 matching lines @@
   }
 } else if (is_mac) {
   import("//build/config/mac/mac_sdk.gni")
   sysroot = mac_sdk_path
 } else if (is_ios) {
   import("//build/config/ios/ios_sdk.gni")
   sysroot = ios_sdk_path
 } else {
   sysroot = ""
 }