JPEGImageDecoder RGB565 and downsample support and related Skia imagegenerator changes

third_party/WebKit/Source/platform/graphics/ImageFrameGenerator.h

Index: third_party/WebKit/Source/platform/graphics/ImageFrameGenerator.h
diff --git a/third_party/WebKit/Source/platform/graphics/ImageFrameGenerator.h b/third_party/WebKit/Source/platform/graphics/ImageFrameGenerator.h
index 39d3c40b00713a5849d327db5aa0bc9b17454317..d939268aa7c11d0d8b989320a103acdf3b093470 100644
--- a/third_party/WebKit/Source/platform/graphics/ImageFrameGenerator.h
+++ b/third_party/WebKit/Source/platform/graphics/ImageFrameGenerator.h
@@ -85,6 +85,9 @@ public:
     // FIXME: Return alpha state for each frame.
     bool hasAlpha(size_t);
 
+    // for single frame, if decoder can produce RGB_565 by decoding current image
+    bool canDecodeToRGB565();
+
     bool getYUVComponentSizes(SkISize componentSizes[3]);
 
 private:
@@ -97,11 +100,11 @@ private:
     void setHasAlpha(size_t index, bool hasAlpha);
 
     // These methods are called while m_decodeMutex is locked.
-    SkBitmap tryToResumeDecode(const SkISize& scaledSize, size_t index);
+    SkBitmap tryToResumeDecode(const SkISize& scaledSize, size_t index, SkColorType outType);

[scroggo_chromium, 2015/10/19 20:41:36]

Maybe this should use an SkImageInfo, and combine the color type and size? Or
would that be confusing since we ignore the other pieces (profile and alpha)?

[aleksandar.stojiljkovic, 2015/10/20 09:51:12]

This is private code for this class.
It comes back to proposal about SkImageGenerator::canDecodeAndScale API (to put
SkImageInfo there) and if Alpha should be part specified or implicitly covered
by RGB565.   

 
     // Use the given decoder to decode. If a decoder is not given then try to create one.
     // Returns true if decoding was complete.
-    bool decode(size_t index, ImageDecoder**, SkBitmap*);
+    bool decode(size_t index, ImageDecoder**, SkBitmap*, SkColorType outType);
 
     SkISize m_fullSize;
     ThreadSafeDataTransport m_data;