Reland of "Update linux sysroot from Wheezy to Jessie"

build/config/sysroot.gni

Index: build/config/sysroot.gni
diff --git a/build/config/sysroot.gni b/build/config/sysroot.gni
index 2bcd6caae1e9a468e7b39f3613c41d2eac5b6ea9..5ea877752a790f7056c7493c10c8ace62a6092bc 100644
--- a/build/config/sysroot.gni
+++ b/build/config/sysroot.gni
@@ -16,10 +16,6 @@ declare_args() {
   target_sysroot_dir = ""
 
   use_sysroot = true
-
-  # TODO(tonikitoo): Remove this arg when wheezy is finally dropped and we
-  # can just use debian/jessie everywhere by default. crbug.com/564904.
-  use_jessie_sysroot = false
 }
 
 if (is_linux && target_sysroot_dir != "") {
@@ -57,20 +53,18 @@ if (is_linux && target_sysroot_dir != "") {
     # 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.
+    # TODO(sbc): This condition can perhaps be eliminated now that we are
+    # using jessie rather than wheezy.
     sysroot = "//build/linux/ubuntu_precise_amd64-sysroot"
   } else {
     if (current_cpu == "x64") {
-      sysroot = "//build/linux/debian_wheezy_amd64-sysroot"
-
-      if (use_jessie_sysroot) {
-        sysroot = "//build/linux/debian_jessie_amd64-sysroot"
-      }
+      sysroot = "//build/linux/debian_jessie_amd64-sysroot"
     } else if (current_cpu == "x86") {
-      sysroot = "//build/linux/debian_wheezy_i386-sysroot"
+      sysroot = "//build/linux/debian_jessie_i386-sysroot"
     } else if (current_cpu == "mipsel") {
-      sysroot = "//build/linux/debian_wheezy_mips-sysroot"
+      sysroot = "//build/linux/debian_jessie_mips-sysroot"
     } else if (current_cpu == "arm") {
-      sysroot = "//build/linux/debian_wheezy_arm-sysroot"
+      sysroot = "//build/linux/debian_jessie_arm-sysroot"
     } else if (current_cpu == "arm64") {
       sysroot = "//build/linux/debian_jessie_arm64-sysroot"
     } else {