Revert "Revert "Reland 2: mac: Use a placeholder string for the family name of the system font." Br…

Source/core/layout/LayoutTextControlMultiLine.cpp

Index: Source/core/layout/LayoutTextControlMultiLine.cpp
diff --git a/Source/core/layout/LayoutTextControlMultiLine.cpp b/Source/core/layout/LayoutTextControlMultiLine.cpp
index 6a67ae7fad0722e19b98b330ec44dd9dfd7ae5bd..b48e0b00ec98de5acff36df47a38347f05fb6ef7 100644
--- a/Source/core/layout/LayoutTextControlMultiLine.cpp
+++ b/Source/core/layout/LayoutTextControlMultiLine.cpp
@@ -24,6 +24,7 @@
 
 #include "core/html/HTMLTextAreaElement.h"
 #include "core/layout/HitTestResult.h"
+#include "core/layout/LayoutTheme.h"
 
 namespace blink {
 
@@ -50,10 +51,11 @@ bool LayoutTextControlMultiLine::nodeAtPoint(HitTestResult& result, const HitTes
 
 float LayoutTextControlMultiLine::getAvgCharWidth(const AtomicString& family) const
 {
-    // Since Lucida Grande is the default font, we want this to match the width
-    // of Courier New, the default font for textareas in IE, Firefox and Safari Win.
-    // 1229 is the avgCharWidth value in the OS/2 table for Courier New.
-    if (family == "Lucida Grande")
+    // Match the default system font to the width of MS Shell Dlg, the default
+    // font for textareas in Firefox, Safari Win and IE for some encodings (in
+    // IE, the default font is encoding specific). 1229 is the avgCharWidth
+    // value in the OS/2 table for Courier New.
+    if (LayoutTheme::theme().needsHackForTextControlWithFontFamily(family))
         return scaleEmToUnits(1229);
 
     return LayoutTextControl::getAvgCharWidth(family);