[css-grid] Fix 1% regression on system_health.memory_desktop

third_party/WebKit/Source/core/style/ComputedStyle.cpp

Index: third_party/WebKit/Source/core/style/ComputedStyle.cpp
diff --git a/third_party/WebKit/Source/core/style/ComputedStyle.cpp b/third_party/WebKit/Source/core/style/ComputedStyle.cpp
index 579565e066cf12e57ea1587261104206f944ed2b..532cb45559541de79a109993cb5f8f3e8272a3fd 100644
--- a/third_party/WebKit/Source/core/style/ComputedStyle.cpp
+++ b/third_party/WebKit/Source/core/style/ComputedStyle.cpp
@@ -2003,7 +2003,8 @@ bool ComputedStyle::shadowListHasCurrentColor(const ShadowList* shadowList)
 static inline Vector<GridTrackSize> initialGridAutoTracks()
 {
     Vector<GridTrackSize> trackSizeList;
-    trackSizeList.append(GridTrackSize(Length(Auto)));
+    trackSizeList.reserveInitialCapacity(1);

[jfernandez, 2016/08/30 11:05:13]

Wouldn't make more sense to pay with Vector's inlineCapacity ? We may get
performance improvements by setting an adjusted inlineCapacity value if we knoe
the vector is going to be small.  Not really sure about the exact value, though.

+    trackSizeList.uncheckedAppend(GridTrackSize(Length(Auto)));
     return trackSizeList;
 }