Allow frames to be free'd even for static images

Source/platform/image-decoders/ImageDecoderTest.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 203 matching lines @@
 TEST(ImageDecoderTest, clearCacheExceptFrameAll)
 {
     const size_t numFrames = 10;
     OwnPtr<TestImageDecoder> decoder(adoptPtr(new TestImageDecoder()));
     decoder->initFrames(numFrames);
     Vector<ImageFrame, 1>& frameBuffers = decoder->frameBufferCache();
     for (size_t i = 0; i < numFrames; ++i)
         frameBuffers[i].setStatus(i % 2 ? ImageFrame::FramePartial : ImageFrame::FrameComplete);
 
     decoder->clearCacheExceptFrame(kNotFound);
-
     for (size_t i = 0; i < numFrames; ++i) {
         SCOPED_TRACE(testing::Message() << i);
         EXPECT_EQ(ImageFrame::FrameEmpty, frameBuffers[i].status());
     }
 }
 
+TEST(ImageDecoderTest, clearCacheExceptFrameAllSingleFrame)
+{
+    OwnPtr<TestImageDecoder> decoder(adoptPtr(new TestImageDecoder()));
+    decoder->initFrames(1);
+    ImageFrame* frame = &decoder->frameBufferCache().first();
+    frame->setStatus(ImageFrame::FrameComplete);
+
+    decoder->clearCacheExceptFrame(kNotFound);
+    EXPECT_EQ(ImageFrame::FrameEmpty, frame->status());
+}
+
 TEST(ImageDecoderTest, clearCacheExceptFramePreverveClearExceptFrame)
 {
     const size_t numFrames = 10;
     OwnPtr<TestImageDecoder> decoder(adoptPtr(new TestImageDecoder()));
     decoder->initFrames(numFrames);
     Vector<ImageFrame, 1>& frameBuffers = decoder->frameBufferCache();
     for (size_t i = 0; i < numFrames; ++i)
         frameBuffers[i].setStatus(ImageFrame::FrameComplete);
 
     decoder->resetRequiredPreviousFrames();
     decoder->clearCacheExceptFrame(5);
     for (size_t i = 0; i < numFrames; ++i) {
         SCOPED_TRACE(testing::Message() << i);
         if (i == 5)
             EXPECT_EQ(ImageFrame::FrameComplete, frameBuffers[i].status());
         else
             EXPECT_EQ(ImageFrame::FrameEmpty, frameBuffers[i].status());
     }
 }