libbase: add parsedouble.h.

Bug: http://b/24905115
Test: run libbase_test --gtest_filter=parsedouble.smoke.
Change-Id: I604424772f2082b420935e6647da03981c0b8929
diff --git a/base/Android.bp b/base/Android.bp
index 88d8ad1..e6ad15b 100644
--- a/base/Android.bp
+++ b/base/Android.bp
@@ -73,6 +73,7 @@
         "errors_test.cpp",
         "file_test.cpp",
         "logging_test.cpp",
+        "parsedouble_test.cpp",
         "parseint_test.cpp",
         "parsenetaddress_test.cpp",
         "quick_exit_test.cpp",