Revert of Allow frames to be free'd even for static images

Source/platform/image-decoders/ImageDecoder.cpp

Index: Source/platform/image-decoders/ImageDecoder.cpp
diff --git a/Source/platform/image-decoders/ImageDecoder.cpp b/Source/platform/image-decoders/ImageDecoder.cpp
index 28c91edfb7aa4d5b0b506a1606a149939a21aad2..cb5774dffc510ff6718f93165df02db3011adc39 100644
--- a/Source/platform/image-decoders/ImageDecoder.cpp
+++ b/Source/platform/image-decoders/ImageDecoder.cpp
@@ -134,6 +134,10 @@
 
 size_t ImageDecoder::clearCacheExceptFrame(size_t clearExceptFrame)
 {
+    // Don't clear if there are no frames or only one frame.
+    if (m_frameBufferCache.size() <= 1)
+        return 0;
+
     size_t frameBytesCleared = 0;
     for (size_t i = 0; i < m_frameBufferCache.size(); ++i) {
         if (i != clearExceptFrame) {