Add null-check to ShapeResult::fallbackFonts

Add a null check for m_runs[i]->m_fontData in ShapeResult::fallbackFonts
to ensure that isTextOrientationFallbackOf is only called when it's set.

TBR=pdr@chromium.org
BUG=629005

Review-Url: https://codereview.chromium.org/2177163003
Cr-Commit-Position: refs/heads/master@{#407633}

third_party/WebKit/Source/platform/fonts/shaping/ShapeResult.cpp

@@ -215,7 +215,8 @@ void ShapeResult::fallbackFonts(HashSet<const SimpleFontData*>* fallback) const
     ASSERT(fallback);
     ASSERT(m_primaryFont);
     for (unsigned i = 0; i < m_runs.size(); ++i) {
-        if (m_runs[i] && m_runs[i]->m_fontData != m_primaryFont
+        if (m_runs[i] && m_runs[i]->m_fontData
+            && m_runs[i]->m_fontData != m_primaryFont
             && !m_runs[i]->m_fontData->isTextOrientationFallbackOf(m_primaryFont.get())) {
             fallback->add(m_runs[i]->m_fontData.get());
         }