Remove unsafe getFontMetrics methods

third_party/WebKit/Source/core/layout/LayoutBlock.cpp

Index: third_party/WebKit/Source/core/layout/LayoutBlock.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutBlock.cpp b/third_party/WebKit/Source/core/layout/LayoutBlock.cpp
index 533e7795aa74dc62a7986affcf706dca4ab6783c..e55c3ab87b8f8bda61bc6ea9878968e41649887d 100644
--- a/third_party/WebKit/Source/core/layout/LayoutBlock.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutBlock.cpp
@@ -1690,7 +1690,12 @@ int LayoutBlock::baselinePosition(FontBaseline baselineType,
   // Note that inline-block counts as replaced here.
   ASSERT(linePositionMode == PositionOfInteriorLineBoxes);
 
-  const FontMetrics& fontMetrics = style(firstLine)->getFontMetrics();
+  const SimpleFontData* fontData = style(firstLine)->font().primaryFont();
+  DCHECK(fontData);
+  if (!fontData)
+    return -1;

[wkorman, 2016/10/13 22:54:30]

Is -1 the correct error value? I see LayoutTheme::baselinePosition() which is
also used as a return value in this method returns 0 in a different
less-error-ish case (!o->isBox()).

[eae, 2016/10/13 23:09:58]

Yeah, -1 is the magic value for unknown baseline.

+
+  const FontMetrics& fontMetrics = fontData->getFontMetrics();
   return (fontMetrics.ascent(baselineType) +
           (lineHeight(firstLine, direction, linePositionMode) -
            fontMetrics.height()) /
@@ -1759,8 +1764,9 @@ int LayoutBlock::inlineBlockBaseline(LineDirectionMode lineDirection) const {
             .toInt();  // Translate to our coordinate space.
     }
   }
-  if (!haveNormalFlowChild && hasLineIfEmpty()) {
-    const FontMetrics& fontMetrics = firstLineStyle()->getFontMetrics();
+  const SimpleFontData* fontData = firstLineStyle()->font().primaryFont();
+  if (!haveNormalFlowChild && hasLineIfEmpty() && fontData) {

[wkorman, 2016/10/13 22:54:30]

Perhaps worth putting fontData first to save on checking others if not available
since hasLineIfEmpty() is a virtual method. Though obviously this situation
should be very rare so not super impactful.

[eae, 2016/10/13 23:09:58]

Acknowledged.

+    const FontMetrics& fontMetrics = fontData->getFontMetrics();
     return (fontMetrics.ascent() +
             (lineHeight(true, lineDirection, PositionOfInteriorLineBoxes) -
              fontMetrics.height()) /