Allowing YUV data to be retrieved from the JPEG Decoder.

Source/platform/graphics/test/MockImageDecoder.h

Index: Source/platform/graphics/test/MockImageDecoder.h
diff --git a/Source/platform/graphics/test/MockImageDecoder.h b/Source/platform/graphics/test/MockImageDecoder.h
index 65e9003c936f03b3517987a21151b6b324524174..af17aa839d03e8a147bbaefacd4cf97e96746798 100644
--- a/Source/platform/graphics/test/MockImageDecoder.h
+++ b/Source/platform/graphics/test/MockImageDecoder.h
@@ -44,7 +44,7 @@ public:
     // MockImageDecoder::decodedSize() to return the same thing as
     // MockImageDecoder::size(). See the precise implementation of
     // MockImageDecoder::decodedSize() below.
-    virtual IntSize decodedSize() const { return IntSize(); }
+    virtual IntSize decodedSize(int component = 0) const { return IntSize(); }
 };
 
 class MockImageDecoder : public ImageDecoder {
@@ -61,9 +61,9 @@ public:
         m_client->decoderBeingDestroyed();
     }
 
-    virtual IntSize decodedSize() const OVERRIDE
+    virtual IntSize decodedSize(int component = 0) const OVERRIDE
     {
-        return m_client->decodedSize().isEmpty() ? size() : m_client->decodedSize();
+        return m_client->decodedSize(component).isEmpty() ? size() : m_client->decodedSize(component);
     }
 
     virtual bool setSize(unsigned width, unsigned height) OVERRIDE