Update from https://crrev.com/306655

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 9ae22183407865cf7c77e65380351f10797ddf8d..e074333cd32a0eb8e99947eac801e4603ba4657f 100644
--- a/build/toolchain/android/BUILD.gn
+++ b/build/toolchain/android/BUILD.gn
@@ -3,6 +3,7 @@
 # found in the LICENSE file.
 
 import("//build/config/sysroot.gni")  # Imports android/config.gni.
+import("//build/toolchain/ccache.gni")
 import("//build/toolchain/clang.gni")
 import("//build/toolchain/goma.gni")
 import("//build/toolchain/gcc_toolchain.gni")
@@ -23,8 +24,8 @@ template("android_gcc_toolchain") {
   gcc_toolchain(target_name) {
     # Make our manually injected libs relative to the build dir.
     android_ndk_lib = rebase_path(
-      invoker.android_ndk_sysroot + "/" + invoker.android_ndk_lib_dir,
-      root_build_dir)
+            invoker.android_ndk_sysroot + "/" + invoker.android_ndk_lib_dir,
+            root_build_dir)
 
     libs_section_prefix = "$android_ndk_lib/crtbegin_dynamic.o"
     libs_section_postfix = "$android_ndk_lib/crtend_android.o"
@@ -36,13 +37,16 @@ template("android_gcc_toolchain") {
     tool_prefix = rebase_path(invoker.tool_prefix, root_build_dir)
 
     if (use_goma) {
-      goma_prefix = "$goma_dir/gomacc "
+      assert(!use_ccache, "Goma and ccache can't be used together.")
+      compiler_prefix = "$goma_dir/gomacc "
+    } else if (use_ccache) {
+      compiler_prefix = "ccache "
     } else {
-      goma_prefix = ""
+      compiler_prefix = ""
     }
 
-    cc = goma_prefix + tool_prefix + "gcc"
-    cxx = goma_prefix + tool_prefix + "g++"
+    cc = compiler_prefix + tool_prefix + "gcc"
+    cxx = compiler_prefix + tool_prefix + "g++"
     ar = tool_prefix + "ar"
     ld = cxx
 
@@ -59,8 +63,10 @@ template("android_gcc_toolchain") {
     android_strip = "${tool_prefix}strip"
 
     mkdir_command = "mkdir -p lib.stripped"
-    strip_command = "$android_strip --strip-unneeded -o $temp_stripped_soname $soname"
-    replace_command = "if ! cmp -s $temp_stripped_soname $stripped_soname; then mv $temp_stripped_soname $stripped_soname; fi"
+    strip_command =
+        "$android_strip --strip-unneeded -o $temp_stripped_soname $soname"
+    replace_command =
+        "if ! cmp -s $temp_stripped_soname $stripped_soname; then mv $temp_stripped_soname $stripped_soname; fi"
     postsolink = "$mkdir_command && $strip_command && $replace_command"
     solink_outputs = [ stripped_soname ]