JPEGImageDecoder RGB565 and downsample support and related Skia imagegenerator changes

third_party/WebKit/Source/platform/graphics/DecodingImageGenerator.cpp

Index: third_party/WebKit/Source/platform/graphics/DecodingImageGenerator.cpp
diff --git a/third_party/WebKit/Source/platform/graphics/DecodingImageGenerator.cpp b/third_party/WebKit/Source/platform/graphics/DecodingImageGenerator.cpp
index a1adcce004f065ad73110d3e77733144419bfd66..446d832b6c3cb5c413f56ae9f6560bc57f3a2bb2 100644
--- a/third_party/WebKit/Source/platform/graphics/DecodingImageGenerator.cpp
+++ b/third_party/WebKit/Source/platform/graphics/DecodingImageGenerator.cpp
@@ -72,13 +72,13 @@ bool DecodingImageGenerator::onGetPixels(const SkImageInfo& info, void* pixels,
         return false;
 
     if (info.colorType() != getInfo().colorType()) {
-        // ImageFrame may have changed the owning SkBitmap to kOpaque_SkAlphaType after sniffing the encoded data, so if we see a request
-        // for opaque, that is ok even if our initial alphatype was not opaque.
-        return false;
+        // So far, only one implemented is RGB565
+        if (info.colorType() != kRGB_565_SkColorType)
+            return false;
     }
 
     PlatformInstrumentation::willDecodeLazyPixelRef(m_generationId);
-    bool decoded = m_frameGenerator->decodeAndScale(getInfo(), m_frameIndex, pixels, rowBytes);
+    bool decoded = m_frameGenerator->decodeAndScale(info, m_frameIndex, pixels, rowBytes);
     PlatformInstrumentation::didDecodeLazyPixelRef();
 
     return decoded;
@@ -125,5 +125,13 @@ SkImageGenerator* DecodingImageGenerator::create(SkData* data)
     return new DecodingImageGenerator(frame, info, 0);
 }
 
+bool DecodingImageGenerator::onCanDecodeAndScale(const SkColorType targetType, const SkScalar scale, SkISize *availableSize, SkISize *lowerSize)

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

nit: I believe the "*" should go next to the type, rather than the name. (I do
not see this explicitly in the Blink style guide, though its examples use that
style, and Chromium's style guide requires it. It also matches the surrounding
code.)

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

Done.

+{
+    if (targetType == kRGB_565_SkColorType && targetType != getInfo().colorType() && scale == SK_Scalar1) {
+        return m_frameGenerator->canDecodeToRGB565();
+    }
+    return DecodingImageGenerator::onCanDecodeAndScale(targetType, scale, availableSize, lowerSize);

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

This looks like infinite recursion, unless I'm missing something? Did you mean
to call SkImageGenerator::onCanDecodeAndScale?

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

Done.

+}
+
 } // namespace blink