Optimized Reflow() some more. In the case where we're not measuring text but

we need to peek ahead and so we need to know the length of the last word, if
there's only one word in the text run then we can avoid measuring

layout/generic/nsTextFrame.cpp

@@ -2611,7 +2611,11 @@ nsTextFrame::Reflow(nsIPresContext& aPresContext,
           if (!measureText) {
             // We didn't measure any text so we don't know lastWordWidth.
             // We have to compute it now
-            if (ts.mSmallCaps) {
+            if (prevOffset == startingOffset) {
+              // There's only one word, so we don't have to measure after all
+              lastWordWidth = x;
+            }
+            else if (ts.mSmallCaps) {
               MeasureSmallCapsText(aReflowState, ts, tx.GetTextAt(prevOffset),
                                    lastWordLen, &lastWordWidth);
             }

layout/html/base/src/nsTextFrame.cpp

@@ -2611,7 +2611,11 @@ nsTextFrame::Reflow(nsIPresContext& aPresContext,
           if (!measureText) {
             // We didn't measure any text so we don't know lastWordWidth.
             // We have to compute it now
-            if (ts.mSmallCaps) {
+            if (prevOffset == startingOffset) {
+              // There's only one word, so we don't have to measure after all
+              lastWordWidth = x;
+            }
+            else if (ts.mSmallCaps) {
               MeasureSmallCapsText(aReflowState, ts, tx.GetTextAt(prevOffset),
                                    lastWordLen, &lastWordWidth);
             }