Bug 1438207 - Finalize the current frame of an ICO decoder correctly. r=tnikkel

Originally we attempted to finalize the current frame from the contained
decoder in nsICODecoder::FinishResource. This is wrong because we
haven't acquired the frame from the contained decoder yet. This happens
in nsICODecoder::GetFinalStateFromContainedDecoder, and so
imgFrame::Finalize call should be moved there. This was causing us to
use fallback image sharing with WebRender after a GPU process crash,
instead of shared surfaces, because it can't get a new file handle for
the surface data until we have finished writing all of the image data.

image/decoders/nsICODecoder.cpp

@@ -100,6 +100,13 @@ nsICODecoder::GetFinalStateFromContainedDecoder()
   mInvalidRect.UnionRect(mInvalidRect, mContainedDecoder->TakeInvalidRect());
   mCurrentFrame = mContainedDecoder->GetCurrentFrameRef();
 
+  // Finalize the frame which we deferred to ensure we could modify the final
+  // result (e.g. to apply the BMP mask).
+  MOZ_ASSERT(!mContainedDecoder->GetFinalizeFrames());
+  if (mCurrentFrame) {
+    mCurrentFrame->FinalizeSurface();
+  }
+
   // Propagate errors.
   nsresult rv = HasError() || mContainedDecoder->HasError()
               ? NS_ERROR_FAILURE
@@ -664,13 +671,6 @@ nsICODecoder::FinishResource()
   MOZ_ASSERT_IF(mContainedDecoder->HasSize(),
                 mContainedDecoder->Size() == mDirEntry->mSize);
 
-  // Finalize the frame which we deferred to ensure we could modify the final
-  // result (e.g. to apply the BMP mask).
-  MOZ_ASSERT(!mContainedDecoder->GetFinalizeFrames());
-  if (mCurrentFrame) {
-    mCurrentFrame->FinalizeSurface();
-  }
-
   return Transition::TerminateSuccess();
 }