Add an option to create unpremultiplied bitmaps.
Currently they cannot be used directly by Skia, but
the pixels can be used elsewhere.

SkImageDecoder:
Add functions to require unpremultiplied output
and query the presence of the requirement

SkImageDecoder_libpng:
SkImageDecoder_libwebp:
SkImageDecoder_WIC:
Respect the requirement for unpremultiplied output.
TODO: Fix SkImageDecoder_CG.

SkScaledBitmapSampler:
Add procs to skip premultiplication and a boolean
parameter to use those procs.

ImageDecodingTest:
Test unpremultiplied bitmap decoding.

SampleUnpremul:
Add a sample which allows visually comparing between the
unpremultiplied version (copied into a premultiplied bitmap,
since drawing unpremultiplied is not currently supported)
and a premultiplied version of image files.

gm.h:
Add a getter for the resource path, so Samples can use it.

As of patch set 13, https://codereview.chromium.org/16816016/
and https://codereview.chromium.org/16983004/, which were
approved separately.

R=reed@google.com

Review URL: https://codereview.chromium.org/16410009

git-svn-id: http://skia.googlecode.com/svn/trunk@9612 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/bench/ImageDecodeBench.cpp b/bench/ImageDecodeBench.cpp
new file mode 100644
index 0000000..1cb29b1
--- /dev/null
+++ b/bench/ImageDecodeBench.cpp
@@ -0,0 +1,91 @@
+/*
+ * 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 "SkBenchmark.h"
+#include "SkBitmap.h"
+#include "SkData.h"
+#include "SkForceLinking.h"
+#include "SkImageDecoder.h"
+#include "SkOSFile.h"
+#include "SkStream.h"
+#include "SkString.h"
+
+__SK_FORCE_IMAGE_DECODER_LINKING;
+
+class SkCanvas;
+
+class ImageDecodeBench : public SkBenchmark {
+public:
+    ImageDecodeBench(void* p, const char* filename)
+    : INHERITED(p)
+    , fName("image_decode_")
+    , fFilename(filename)
+    , fStream()
+    , fValid(false) {
+        fName.append(SkOSPath::SkBasename(filename));
+        fIsRendering = false;
+    }
+
+protected:
+    virtual const char* onGetName() SK_OVERRIDE {
+        return fName.c_str();
+    }
+
+    virtual void onPreDraw() SK_OVERRIDE {
+        SkFILEStream fileStream(fFilename.c_str());
+        fValid = fileStream.isValid() && fileStream.getLength() > 0;
+        if (fValid) {
+            const size_t size = fileStream.getLength();
+            void* data = sk_malloc_throw(size);
+            if (fileStream.read(data, size) < size) {
+                fValid = false;
+            } else {
+                SkAutoTUnref<SkData> skdata(SkData::NewFromMalloc(data, size));
+                fStream.setData(skdata.get());
+            }
+        }
+    }
+
+    virtual void onDraw(SkCanvas*) SK_OVERRIDE {
+#ifdef SK_DEBUG
+        if (!fValid) {
+            SkDebugf("stream was invalid: %s\n", fName.c_str());
+            return;
+        }
+#endif
+        // Decode a bunch of times
+        SkBitmap bm;
+        for (int i = 0; i < SkBENCHLOOP(1000); ++i) {
+            SkDEBUGCODE(bool success =) SkImageDecoder::DecodeStream(&fStream, &bm);
+#ifdef SK_DEBUG
+            if (!success) {
+                SkDebugf("failed to decode %s\n", fName.c_str());
+                return;
+            }
+#endif
+            SkDEBUGCODE(success =) fStream.rewind();
+#ifdef SK_DEBUG
+            if (!success) {
+                SkDebugf("failed to rewind %s\n", fName.c_str());
+                return;
+            }
+#endif
+        }
+    }
+
+private:
+    SkString        fName;
+    const SkString  fFilename;
+    SkMemoryStream  fStream;
+    bool            fValid;
+
+    typedef SkBenchmark INHERITED;
+};
+
+// These are files which call decodePalette
+//DEF_BENCH( return SkNEW_ARGS(ImageDecodeBench, (p, "/usr/local/google/home/scroggo/Downloads/images/hal_163x90.png")); )
+//DEF_BENCH( return SkNEW_ARGS(ImageDecodeBench, (p, "/usr/local/google/home/scroggo/Downloads/images/box_19_top-left.png")); )