Remove unused tools and unused includes of SkImageDecoder

tools/test_image_decoder.cpp

-/*
- * Copyright 2013 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#include "SkBitmap.h"
-#include "SkForceLinking.h"
-#include "SkGraphics.h"
-#include "SkImageDecoder.h"
-
-__SK_FORCE_IMAGE_DECODER_LINKING;
-
-/**
-   Simple program to test Skia's ability to decode images without
-   errors or debug messages. */
-int tool_main(int argc, char** argv);
-int tool_main(int argc, char** argv) {
-    if (argc < 2) {
-        SkDebugf("Usage:\n %s imagefile\n\n", argv[0]);
-        return 3;
-    }
-    SkAutoGraphics ag;  // Enable use of SkRTConfig
-    SkBitmap bitmap;
-    if (!(SkImageDecoder::DecodeFile(argv[1], &bitmap))) {
-        return 2;
-    }
-    if (bitmap.empty()) {
-        return 1;
-    }
-    return 0;
-}
-
-#if !defined SK_BUILD_FOR_IOS
-int main(int argc, char * const argv[]) {
-    return tool_main(argc, (char**) argv);
-}
-#endif