Gn: remove redundant prefix setting code.

build/toolchain/android/BUILD.gn

Index: build/toolchain/android/BUILD.gn
diff --git a/build/toolchain/android/BUILD.gn b/build/toolchain/android/BUILD.gn
index c2b82f3f258b9d2739d1c33d5ce1cbc2a91da1de..2e47b2d179adfd032636799634c03dc57c5c6145 100644
--- a/build/toolchain/android/BUILD.gn
+++ b/build/toolchain/android/BUILD.gn
@@ -13,8 +13,6 @@ import("//build/toolchain/gcc_toolchain.gni")
 #      Sysroot for this architecture.
 #  - android_ndk_lib_dir
 #      Subdirectory inside of android_ndk_sysroot where libs go.
-#  - tool_prefix
-#      Prefix to be added to the tool names.
 #  - toolchain_cpu
 #      Same as gcc_toolchain
 template("android_gcc_toolchain") {
@@ -31,7 +29,7 @@ template("android_gcc_toolchain") {
     solink_libs_section_postfix = "$android_ndk_lib/crtend_so.o"
 
     # The tools should be run relative to the build dir.
-    tool_prefix = rebase_path(invoker.tool_prefix, root_build_dir)
+    tool_prefix = rebase_path("$android_tool_prefix", root_build_dir)
 
     is_clang = invoker.is_clang
     if (is_clang) {
@@ -62,14 +60,12 @@ template("android_gcc_toolchains_helper") {
   android_gcc_toolchain(target_name) {
     android_ndk_sysroot = invoker.android_ndk_sysroot
     android_ndk_lib_dir = invoker.android_ndk_lib_dir
-    tool_prefix = invoker.tool_prefix
     toolchain_cpu = invoker.toolchain_cpu
   }
 
   android_gcc_toolchain("clang_$target_name") {
     android_ndk_sysroot = invoker.android_ndk_sysroot
     android_ndk_lib_dir = invoker.android_ndk_lib_dir
-    tool_prefix = invoker.tool_prefix
     toolchain_cpu = invoker.toolchain_cpu
     is_clang = true
   }
@@ -79,7 +75,6 @@ android_gcc_toolchains_helper("x86") {
   android_ndk_sysroot = "$android_ndk_root/$x86_android_sysroot_subdir"
   android_ndk_lib_dir = "usr/lib"
 
-  tool_prefix = "$x86_android_toolchain_root/bin/i686-linux-android-"
   toolchain_cpu = "x86"
 }
 
@@ -87,7 +82,6 @@ android_gcc_toolchains_helper("arm") {
   android_ndk_sysroot = "$android_ndk_root/$arm_android_sysroot_subdir"
   android_ndk_lib_dir = "usr/lib"
 
-  tool_prefix = "$arm_android_toolchain_root/bin/arm-linux-androideabi-"
   toolchain_cpu = "arm"
 }
 
@@ -95,7 +89,6 @@ android_gcc_toolchains_helper("mipsel") {
   android_ndk_sysroot = "$android_ndk_root/$mips_android_sysroot_subdir"
   android_ndk_lib_dir = "usr/lib"
 
-  tool_prefix = "$mips_android_toolchain_root/bin/mipsel-linux-android-"
   toolchain_cpu = "mipsel"
 }
 
@@ -103,7 +96,6 @@ android_gcc_toolchains_helper("x64") {
   android_ndk_sysroot = "$android_ndk_root/$x86_64_android_sysroot_subdir"
   android_ndk_lib_dir = "usr/lib64"
 
-  tool_prefix = "$x86_64_android_toolchain_root/bin/x86_64-linux-android-"
   toolchain_cpu = "x86_64"
 }
 
@@ -111,7 +103,6 @@ android_gcc_toolchains_helper("arm64") {
   android_ndk_sysroot = "$android_ndk_root/$arm64_android_sysroot_subdir"
   android_ndk_lib_dir = "usr/lib"
 
-  tool_prefix = "$arm64_android_toolchain_root/bin/aarch64-linux-android-"
   toolchain_cpu = "aarch64"
 }
 
@@ -119,6 +110,5 @@ android_gcc_toolchains_helper("mips64el") {
   android_ndk_sysroot = "$android_ndk_root/$mips64_android_sysroot_subdir"
   android_ndk_lib_dir = "usr/lib64"
 
-  tool_prefix = "$mips64_android_toolchain_root/bin/mips64el-linux-android-"
   toolchain_cpu = "mipsel64el"
 }