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/gl/glutil/context_darwin_amd64.go

Index: third_party/go/src/golang.org/x/mobile/gl/glutil/context_darwin_amd64.go
diff --git a/third_party/go/src/golang.org/x/mobile/gl/glutil/context_darwin_amd64.go b/third_party/go/src/golang.org/x/mobile/gl/glutil/context_darwin_amd64.go
deleted file mode 100644
index 63cbc10a591734fbac24442258cbb97d0b193ed9..0000000000000000000000000000000000000000
--- a/third_party/go/src/golang.org/x/mobile/gl/glutil/context_darwin_amd64.go
+++ /dev/null
@@ -1,75 +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 darwin
-
-package glutil
-
-// TODO(crawshaw): Only used in glutil tests for now (cgo is not support in _test.go files).
-// TODO(crawshaw): Export some kind of Context. Work out what we can offer, where. Maybe just for tests.
-// TODO(crawshaw): Support android and windows.
-
-/*
-#cgo LDFLAGS: -framework OpenGL
-#import <OpenGL/OpenGL.h>
-#import <OpenGL/gl3.h>
-
-void CGCreate(CGLContextObj* ctx) {
-	CGLPixelFormatAttribute attributes[] = {
-		kCGLPFAOpenGLProfile, (CGLPixelFormatAttribute)kCGLOGLPVersion_3_2_Core,
-		kCGLPFAColorSize, (CGLPixelFormatAttribute)24,
-		kCGLPFAAlphaSize, (CGLPixelFormatAttribute)8,
-		kCGLPFADepthSize, (CGLPixelFormatAttribute)16,
-		kCGLPFAAccelerated,
-		kCGLPFADoubleBuffer,
-		(CGLPixelFormatAttribute) 0
-	};
-	CGLPixelFormatObj pix;
-	GLint num;
-	CGLChoosePixelFormat(attributes, &pix, &num);
-	CGLCreateContext(pix, 0, ctx);
-	CGLDestroyPixelFormat(pix);
-	CGLSetCurrentContext(*ctx);
-	CGLLockContext(*ctx);
-}
-*/
-import "C"
-
-import "runtime"
-
-// contextGL holds a copy of the OpenGL Context from thread-local storage.
-//
-// Do not move a contextGL between goroutines or OS threads.
-type contextGL struct {
-	ctx C.CGLContextObj
-}
-
-// createContext creates an OpenGL context, binds it as the current context
-// stored in thread-local storage, and locks the current goroutine to an os
-// thread.
-func createContext() *contextGL {
-	// The OpenGL active context is stored in TLS.
-	runtime.LockOSThread()
-
-	c := new(contextGL)
-	C.CGCreate(&c.ctx)
-
-	// Using attribute arrays in OpenGL 3.3 requires the use of a VBA.
-	// But VBAs don't exist in ES 2. So we bind a default one.
-	var id C.GLuint
-	C.glGenVertexArrays(1, &id)
-	C.glBindVertexArray(id)
-
-	return c
-}
-
-// destroy destroys an OpenGL context and unlocks the current goroutine from
-// its os thread.
-func (c *contextGL) destroy() {
-	C.CGLUnlockContext(c.ctx)
-	C.CGLSetCurrentContext(nil)
-	C.CGLDestroyContext(c.ctx)
-	c.ctx = nil
-	runtime.UnlockOSThread()
-}