GIF: Use SkTArray instead of std::vector

Speculative fix for a memory regression seen in Chromium. Chromium
previously used a WTF::Vector, which has a growth factor of 1.5, as does
SkTArray. Depending on the implementation of std::vector, this may slow
the allocation of memory.

Bug: 758946
Change-Id: I323390027467e32a6c66667c927fae0aba292446
Reviewed-on: https://skia-review.googlesource.com/40777
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Leon Scroggins <scroggo@google.com>

1 files changed, 6 insertions, 8 deletions

diff --git a/third_party/gif/SkGifImageReader.cpp b/third_party/gif/SkGifImageReader.cpp
index ed20af017b..990da5618b 100644
--- a/third_party/gif/SkGifImageReader.cpp
+++ b/third_party/gif/SkGifImageReader.cpp
@@ -344,7 +344,7 @@ sk_sp<SkColorTable> SkGIFColorMap::buildTable(SkStreamBuffer* streamBuffer, SkCo
 }
 
 sk_sp<SkColorTable> SkGifImageReader::getColorTable(SkColorType colorType, int index) {
-    if (index < 0 || static_cast<size_t>(index) >= m_frames.size()) {
+    if (index < 0 || index >= m_frames.count()) {
         return nullptr;
     }
 
@@ -382,8 +382,7 @@ bool SkGIFFrameContext::decode(SkStreamBuffer* streamBuffer, SkGifCodec* client,
     }
 
     // Some bad GIFs have extra blocks beyond the last row, which we don't want to decode.
-    while (static_cast<size_t>(m_currentLzwBlock) < m_lzwBlocks.size()
-           && m_lzwContext->hasRemainingRows()) {
+    while (m_currentLzwBlock < m_lzwBlocks.count() && m_lzwContext->hasRemainingRows()) {
         const auto& block = m_lzwBlocks[m_currentLzwBlock];
         const size_t len = block.blockSize;
 
@@ -430,7 +429,7 @@ SkCodec::Result SkGifImageReader::parse(SkGifImageReader::SkGIFParseQuery query)
 
     // SkGIFSizeQuery and SkGIFFrameCountQuery are negative, so this is only meaningful when >= 0.
     const int lastFrameToParse = (int) query;
-    if (lastFrameToParse >= 0 && (int) m_frames.size() > lastFrameToParse
+    if (lastFrameToParse >= 0 && m_frames.count() > lastFrameToParse
                 && m_frames[lastFrameToParse]->isComplete()) {
         // We have already parsed this frame.
         return SkCodec::kSuccess;
@@ -823,7 +822,7 @@ SkCodec::Result SkGifImageReader::parse(SkGifImageReader::SkGIFParseQuery query)
                 // decode all rows but we treat it as frame complete.
                 m_frames.back()->setComplete();
                 GETN(1, SkGIFImageStart);
-                if (lastFrameToParse >= 0 && (int) m_frames.size() > lastFrameToParse) {
+                if (lastFrameToParse >= 0 && m_frames.count() > lastFrameToParse) {
                     m_streamBuffer.flush();
                     return SkCodec::kSuccess;
                 }
@@ -874,9 +873,8 @@ bool SkGifImageReader::hasTransparency(int transparentPixel, bool isLocalColorma
 void SkGifImageReader::addFrameIfNecessary()
 {
     if (m_frames.empty() || m_frames.back()->isComplete()) {
-        const size_t i = m_frames.size();
-        std::unique_ptr<SkGIFFrameContext> frame(new SkGIFFrameContext(this, static_cast<int>(i)));
-        m_frames.push_back(std::move(frame));
+        const int i = m_frames.count();
+        m_frames.emplace_back(new SkGIFFrameContext(this, i));
     }
 }