Remove third_party/golang.org/x/mobile as it is no longer used with Go 1.5.

third_party/go/src/golang.org/x/mobile/f32/gen.go

Index: third_party/go/src/golang.org/x/mobile/f32/gen.go
diff --git a/third_party/go/src/golang.org/x/mobile/f32/gen.go b/third_party/go/src/golang.org/x/mobile/f32/gen.go
deleted file mode 100644
index 8f8b1871a928d7a372b59c172d55982ee7ec0b7a..0000000000000000000000000000000000000000
--- a/third_party/go/src/golang.org/x/mobile/f32/gen.go
+++ /dev/null
@@ -1,48 +0,0 @@
-// Copyright 2014 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// +build ignore
-
-package main
-
-/*
-This program generates table.go. Invoke it as:
-go run gen.go -output table.go
-*/
-
-import (
-	"bytes"
-	"flag"
-	"fmt"
-	"go/format"
-	"io/ioutil"
-	"log"
-	"math"
-)
-
-// N is the number of entries in the sin look-up table. It must be a power of 2.
-const N = 4096
-
-var filename = flag.String("output", "table.go", "output file name")
-
-func main() {
-	b := new(bytes.Buffer)
-	fmt.Fprintf(b, "// generated by go run gen.go; DO NOT EDIT\n\npackage f32\n\n")
-	fmt.Fprintf(b, "const sinTableLen = %d\n\n", N)
-	fmt.Fprintf(b, "// sinTable[i] equals sin(i * π / sinTableLen).\n")
-	fmt.Fprintf(b, "var sinTable = [sinTableLen]float32{\n")
-	for i := 0; i < N; i++ {
-		radians := float64(i) * (math.Pi / N)
-		fmt.Fprintf(b, "%v,\n", float32(math.Sin(radians)))
-	}
-	fmt.Fprintf(b, "}\n")
-
-	data, err := format.Source(b.Bytes())
-	if err != nil {
-		log.Fatal(err)
-	}
-	if err := ioutil.WriteFile(*filename, data, 0644); err != nil {
-		log.Fatal(err)
-	}
-}