Snap inline box boundaries to layout units during line breaking.

third_party/WebKit/Source/core/layout/line/BreakingContextInlineHeaders.h

Index: third_party/WebKit/Source/core/layout/line/BreakingContextInlineHeaders.h
diff --git a/third_party/WebKit/Source/core/layout/line/BreakingContextInlineHeaders.h b/third_party/WebKit/Source/core/layout/line/BreakingContextInlineHeaders.h
index 061e927fb62678ebf188a774f12dbe57c8b1a95a..846bca474bd59dd5a7a5467a03b90a674a6ab462 100644
--- a/third_party/WebKit/Source/core/layout/line/BreakingContextInlineHeaders.h
+++ b/third_party/WebKit/Source/core/layout/line/BreakingContextInlineHeaders.h
@@ -278,6 +278,12 @@ inline void BreakingContext::increment()
         m_currentCharacterIsSpace = false;
 
     m_current.moveToStartOf(m_nextObject);
+
+    // When the line box tree is created, this position in the line will be snapped to
+    // LayoutUnit's, and those measurements will be used by the paint code.  Do the
+    // equivalent snapping here, to get consistent line measurements.
+    m_width.snapUncommittedWidth();
+
     m_atStart = false;
 }