Allow frames to be free'd even for static images

Source/platform/image-decoders/ImageDecoderTest.cpp

Index: Source/platform/image-decoders/ImageDecoderTest.cpp
diff --git a/Source/platform/image-decoders/ImageDecoderTest.cpp b/Source/platform/image-decoders/ImageDecoderTest.cpp
index 9d4ba3b742ff66f2af84ea671d46183ebb22e146..5d54bb117203e91b59740eb336844165b44a0014 100644
--- a/Source/platform/image-decoders/ImageDecoderTest.cpp
+++ b/Source/platform/image-decoders/ImageDecoderTest.cpp
@@ -228,6 +228,18 @@ TEST(ImageDecoderTest, clearCacheExceptFrameAll)
     }
 }
 
+TEST(ImageDecoderTest, clearCacheExceptFrameAllSingleFrame)
+{
+    OwnPtr<TestImageDecoder> decoder(adoptPtr(new TestImageDecoder()));
+    decoder->initFrames(1);
+    Vector<ImageFrame, 1>& frameBuffers = decoder->frameBufferCache();

[Peter Kasting, 2014/01/14 00:46:18]

Nit: What about:

ImageFrame* frame = &decoder->frameBufferCache().first();

Then you can use "frame->" in both places below, which seems clearer.

[fs, 2014/01/14 08:32:09]

Agreed. Will change.

+    frameBuffers[0].setStatus(ImageFrame::FrameComplete);
+
+    decoder->clearCacheExceptFrame(kNotFound);
+
+    EXPECT_EQ(ImageFrame::FrameEmpty, frameBuffers[0].status());
+}
+
 TEST(ImageDecoderTest, clearCacheExceptFramePreverveClearExceptFrame)
 {
     const size_t numFrames = 10;