Use better heuristic for maxcharwidth.

Related skia change:
https://codereview.chromium.org/692083002/

BUG=420901

Review URL: https://codereview.chromium.org/718673004

git-svn-id: svn://svn.chromium.org/blink/trunk@185157 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/platform/fonts/SimpleFontData.cpp

@@ -201,10 +201,10 @@ void SimpleFontData::platformInit()
     // https://crbug.com/420901
     m_maxCharWidth = std::max(m_avgCharWidth, m_fontMetrics.floatAscent());
 #else
-    // FIXME: This seems incorrect and should probably use fMaxCharWidth as
-    // the code path above.
-    SkScalar xRange = metrics.fXMax - metrics.fXMin;
-    m_maxCharWidth = SkScalarRoundToInt(xRange * SkScalarRoundToInt(m_platformData.size()));
+    // Better would be to rely on either fMaxCharWidth or fAveCharWidth.
+    // skbug.com/3087
+    m_maxCharWidth = SkScalarRoundToInt(metrics.fXMax - metrics.fXMin);
+
 #endif
 
 #if !OS(MACOSX)

third_party/WebKit/public/blink_skia_config.gypi

@@ -11,6 +11,7 @@
     # AFTER the flag has been removed from skia.gyp in Chromium.
     'blink_skia_defines': [
           'SK_FM_NEW_MATCH_FAMILY_STYLE_CHARACTER=1',
+          'SK_USE_SCALED_FONTMETRICS',
     ],
   },
 }