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..d1814934929f549f513a6f171004faaaefa7b354 100644
--- a/third_party/WebKit/Source/platform/graphics/DecodingImageGenerator.cpp
+++ b/third_party/WebKit/Source/platform/graphics/DecodingImageGenerator.cpp
@@ -67,18 +67,14 @@ bool DecodingImageGenerator::onGetPixels(const SkImageInfo& info, void* pixels,
 {
     TRACE_EVENT1("blink", "DecodingImageGenerator::getPixels", "index", static_cast<int>(m_frameIndex));
 
-    // Implementation doesn't support scaling yet so make sure we're not given a different size.
-    if (info.width() != getInfo().width() || info.height() != getInfo().height())
-        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 +121,22 @@ SkImageGenerator* DecodingImageGenerator::create(SkData* data)
     return new DecodingImageGenerator(frame, info, 0);
 }
 
+SkImageGenerator::Result DecodingImageGenerator::onCanDecodeAndScale(const SkColorType targetType,
+    const SkScalar scale, SkISize* availableSize, SkISize* lowerSize)
+{
+    SkColorType readC = targetType;
+    float desired = SkScalarToFloat(scale);
+    float read = desired;
+    float lower = 0;
+    m_frameGenerator->getAvailableDecodeAndScale(&readC, &read, &lower);
+    if (availableSize)
+        availableSize->set(static_cast<int>(ceil(getInfo().width() * read)), static_cast<int>(ceil(getInfo().height() * read)));
+    if (lowerSize)
+        lowerSize->set(static_cast<int>(ceil(getInfo().width() * lower)), static_cast<int>(ceil(getInfo().height() * lower)));
+
+    return static_cast<SkImageGenerator::Result>(((desired != 1.0f && read != 1.0f) ? SkImageGenerator::kScale : SkImageGenerator::kNotAvailable)
+        | ((readC == targetType) ? SkImageGenerator::kDecode : SkImageGenerator::kNotAvailable));
+}
+
 } // namespace blink