Adding blink side flag that allows disabling YUV decoding

Source/platform/graphics/DecodingImageGenerator.cpp

Index: Source/platform/graphics/DecodingImageGenerator.cpp
diff --git a/Source/platform/graphics/DecodingImageGenerator.cpp b/Source/platform/graphics/DecodingImageGenerator.cpp
index 4aa8a6dbffc57813ed87c567d7548c35d2586c47..3ab659ab14d85b410dcc761bce11de132d67caf4 100644
--- a/Source/platform/graphics/DecodingImageGenerator.cpp
+++ b/Source/platform/graphics/DecodingImageGenerator.cpp
@@ -35,6 +35,18 @@
 
 namespace blink {
 
+bool DecodingImageGenerator::s_yuvDecodingEnabled = false;
+
+void DecodingImageGenerator::setYUVDecodingEnabled(bool enabled)
+{
+    s_yuvDecodingEnabled = enabled;
+}
+
+bool DecodingImageGenerator::yuvDecodingEnabled()
+{
+    return s_yuvDecodingEnabled;
+}
+
 DecodingImageGenerator::DecodingImageGenerator(PassRefPtr<ImageFrameGenerator> frameGenerator, const SkImageInfo& info, size_t index)
     : m_frameGenerator(frameGenerator)
     , m_imageInfo(info)
@@ -85,9 +97,11 @@ bool DecodingImageGenerator::onGetPixels(const SkImageInfo& info, void* pixels,
 
 bool DecodingImageGenerator::onGetYUV8Planes(SkISize sizes[3], void* planes[3], size_t rowBytes[3], SkYUVColorSpace* colorSpace)
 {
-    if (!planes || !planes[0]) {
+    if (!yuvDecodingEnabled())
+        return false;
+
+    if (!planes || !planes[0])
         return m_frameGenerator->getYUVComponentSizes(sizes);
-    }
 
     TRACE_EVENT0("blink", "DecodingImageGenerator::onGetYUV8Planes");
     PlatformInstrumentation::willDecodeLazyPixelRef(m_generationId);