Fix ImageDecoder::frameIsCompleteAtIndex - fully received instead of decoded.

third_party/WebKit/Source/platform/image-decoders/gif/GIFImageDecoder.cpp

Index: third_party/WebKit/Source/platform/image-decoders/gif/GIFImageDecoder.cpp
diff --git a/third_party/WebKit/Source/platform/image-decoders/gif/GIFImageDecoder.cpp b/third_party/WebKit/Source/platform/image-decoders/gif/GIFImageDecoder.cpp
index 457666d25dbf9719bca561b730007b49d180edd0..b66cbf32adb306c620d9cd7f9c34496393b2baa1 100644
--- a/third_party/WebKit/Source/platform/image-decoders/gif/GIFImageDecoder.cpp
+++ b/third_party/WebKit/Source/platform/image-decoders/gif/GIFImageDecoder.cpp
@@ -83,9 +83,10 @@ int GIFImageDecoder::repetitionCount() const
     return m_repetitionCount;
 }
 
-bool GIFImageDecoder::frameIsCompleteAtIndex(size_t index) const
+bool GIFImageDecoder::frameIsFullyReceivedAtIndex(size_t index) const
 {
-    return m_reader && (index < m_reader->imagesCount()) && m_reader->frameContext(index)->isComplete();
+    return (m_reader && (index < m_reader->imagesCount()) && m_reader->frameContext(index)->isComplete())
+        || ImageDecoder::frameIsFullyReceivedAtIndex(index);

[scroggo_chromium, 2016/05/23 16:40:42]

This will incorporate m_failed, as Peter suggested in [1]. But it seems that it
could return true if there are e.g. 2 frames, and a client calls
frameIsFullyReceivedAtIndex(<some number greater than 2>). Is that okay? 

[1]
https://codereview.chromium.org/1962563002/diff/20001/third_party/WebKit/Sour...

[aleksandar.stojiljkovic, 2016/05/24 11:08:24]

Thanks.
Bounds check was missing in ImageDecoder::frameIsFullyReceivedAtIndex - it
wasn't OK to return only m_isAllDataReceived.

Related to question here, yes makes sense to check on bounds also for failed() -
as frame count was or wasn't calculated properly before failed.

 }
 
 float GIFImageDecoder::frameDurationAtIndex(size_t index) const