Remove unused tools and unused includes of SkImageDecoder

tools/imgconv.cpp

-/*
- * Copyright 2014 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 "SkGraphics.h"
-#include "SkImageDecoder.h"
-#include "SkImageEncoder.h"
-#include "SkString.h"
-
-int tool_main(int argc, char** argv);
-int tool_main(int argc, char** argv) {
-    SkAutoGraphics ag;
-
-    for (int i = 1; i < argc; ++i) {
-        SkString src(argv[i]);
-        if (src.endsWith(".png")) {
-            SkString dst(src.c_str(), src.size() - 4);
-            dst.append(".jpg");
-
-            SkBitmap bm;
-            if (SkImageDecoder::DecodeFile(src.c_str(), &bm)) {
-                if (SkImageEncoder::EncodeFile(dst.c_str(), bm, SkImageEncoder::kJPEG_Type, 100)) {
-                    SkDebugf("converted %s to %s\n", src.c_str(), dst.c_str());
-                } else {
-                    SkDebugf("failed to encode %s\n", src.c_str());
-                }
-            } else {
-                SkDebugf("failed to decode %s\n", src.c_str());
-            }
-        }
-    }
-    return 0;
-}
-
-#if !defined SK_BUILD_FOR_IOS
-int main(int argc, char * const argv[]) {
-    return tool_main(argc, (char**) argv);
-}
-#endif