From 163196360efde10281e5c0492fd6cb2e9318eec0 Mon Sep 17 00:00:00 2001
From: Nicholas Nethercote <nnethercote@mozilla.com>
Date: Sun, 8 Nov 2015 14:48:58 -0800
Subject: [PATCH] Bug 1038663 (part 3, attempt 2) - Factor out space width
 computation. r=heycam.

---
 layout/generic/nsTextFrame.cpp | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/layout/generic/nsTextFrame.cpp b/layout/generic/nsTextFrame.cpp
index 21a62b7f4405..59edf75dab95 100644
--- a/layout/generic/nsTextFrame.cpp
+++ b/layout/generic/nsTextFrame.cpp
@@ -1607,6 +1607,19 @@ GetFirstFontMetrics(gfxFontGroup* aFontGroup, bool aVerticalMetrics)
                                            : gfxFont::eHorizontal);
 }
 
+static gfxFloat
+GetSpaceWidthAppUnits(gfxTextRun* aTextRun)
+{
+  // Round the space width when converting to appunits the same way textruns
+  // do.
+  gfxFloat spaceWidthAppUnits =
+    NS_round(GetFirstFontMetrics(aTextRun->GetFontGroup(),
+                                 aTextRun->UseCenterBaseline()).spaceWidth *
+             aTextRun->GetAppUnitsPerDevUnit());
+
+  return spaceWidthAppUnits;
+}
+
 static nscoord
 LetterSpacing(nsIFrame* aFrame, const nsStyleText* aStyleText = nullptr)
 {
@@ -3225,14 +3238,8 @@ ComputeTabWidthAppUnits(nsIFrame* aFrame, gfxTextRun* aTextRun)
 {
   // Get the number of spaces from CSS -moz-tab-size
   const nsStyleText* textStyle = aFrame->StyleText();
-  
-  // Round the space width when converting to appunits the same way
-  // textruns do
-  gfxFloat spaceWidthAppUnits =
-    NS_round(GetFirstFontMetrics(aTextRun->GetFontGroup(),
-                                 aTextRun->UseCenterBaseline()).spaceWidth *
-             aTextRun->GetAppUnitsPerDevUnit());
-  return textStyle->mTabSize * spaceWidthAppUnits;
+
+  return textStyle->mTabSize * GetSpaceWidthAppUnits(aTextRun);
 }
 
 // aX and the result are in whole appunits.