Test region decoding in skimage, plus fixes.

Add tests in skimage to perform region decoding. Write out a
PNG of the region as well as a bitmap obtained with extractSubset
for comparison.

Rename decodeRegion to decodeSubset, so it will not be confused
with SkRegion. (Leave a function called decodeRegion which calls
decodeSubset.)

Clean up some comments.

Use png_set_interlaced_pass instead of modifying pass directly.

Make some changes to region decoding to fix problems I discovered
during testing:

Only call getAddr within a valid range.
Check for a NULL fInputStream.
Return a boolean for whether cropBitmap succeeded.
In cropBitmap, do not attempt to draw to a bitmap to an Index8
bitmap, which crashes. Use extractSubset instead.
Remove an assert.

R=djsollen@google.com

Review URL: https://codereview.chromium.org/14567011

git-svn-id: http://skia.googlecode.com/svn/trunk@8996 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 2 insertions, 2 deletions

diff --git a/src/images/SkImageDecoder_libwebp.cpp b/src/images/SkImageDecoder_libwebp.cpp
index a33d0f9b2f..e623f376d7 100644
--- a/src/images/SkImageDecoder_libwebp.cpp
+++ b/src/images/SkImageDecoder_libwebp.cpp
@@ -111,7 +111,7 @@ public:
 
 protected:
     virtual bool onBuildTileIndex(SkStream *stream, int *width, int *height) SK_OVERRIDE;
-    virtual bool onDecodeRegion(SkBitmap* bitmap, const SkIRect& rect) SK_OVERRIDE;
+    virtual bool onDecodeSubset(SkBitmap* bitmap, const SkIRect& rect) SK_OVERRIDE;
     virtual bool onDecode(SkStream* stream, SkBitmap* bm, Mode) SK_OVERRIDE;
 
 private:
@@ -321,7 +321,7 @@ static bool is_config_compatible(const SkBitmap& bitmap) {
            config == SkBitmap::kARGB_8888_Config;
 }
 
-bool SkWEBPImageDecoder::onDecodeRegion(SkBitmap* decodedBitmap,
+bool SkWEBPImageDecoder::onDecodeSubset(SkBitmap* decodedBitmap,
                                         const SkIRect& region) {
     SkIRect rect = SkIRect::MakeWH(fOrigWidth, fOrigHeight);