Initiate webfont download right after style recalc

Source/core/css/CSSFontFace.cpp

Index: Source/core/css/CSSFontFace.cpp
diff --git a/Source/core/css/CSSFontFace.cpp b/Source/core/css/CSSFontFace.cpp
index 960eb6045ecc6725779776f5161192588bdb218e..1a62acb9f9439468aa41d584a9888c9e2f2ae775 100644
--- a/Source/core/css/CSSFontFace.cpp
+++ b/Source/core/css/CSSFontFace.cpp
@@ -84,6 +84,7 @@ void CSSFontFace::fontLoaded(CSSFontFaceSource* source)
 {
     if (source != m_activeSource)
         return;
+    m_activeSource = 0;
 
     // FIXME: Can we assert that m_segmentedFontFace is non-null? That may
     // require stopping in-progress font loading when the last
@@ -137,7 +138,16 @@ PassRefPtr<SimpleFontData> CSSFontFace::getFontData(const FontDescription& fontD
 
 void CSSFontFace::willUseFontData(const FontDescription& fontDescription)
 {
-    if (loadStatus() != FontFace::Unloaded)
+    if (loadStatus() != FontFace::Unloaded || m_activeSource)
+        return;
+
+    // Kicks off font load here only if the @font-face has no unicode-range.
+    // @font-faces with unicode-range will be loaded when a GlyphPage for the
+    // font is created.
+    // FIXME: Pass around the text to render from RenderText, and kick download
+    // if m_ranges intersects with the text. Make sure this does not cause
+    // performance regression.
+    if (!m_ranges.isEntireRange())
         return;
 
     ASSERT(m_segmentedFontFace);
@@ -146,8 +156,10 @@ void CSSFontFace::willUseFontData(const FontDescription& fontDescription)
     for (size_t i = 0; i < size; ++i) {
         if (!m_sources[i]->isValid() || (m_sources[i]->isLocal() && !m_sources[i]->isLocalFontAvailable(fontDescription)))
             continue;
-        if (!m_sources[i]->isLocal())
+        if (!m_sources[i]->isLocal()) {
+            m_activeSource = m_sources[i].get();

[dglazkov, 2013/11/12 17:58:56]

As an aside, I am struggling to understand the purpose of m_activeSource. Is
this just a boolean that's implemented as a pointer? We should probably turn it
into a bool then.

             m_sources[i]->willUseFontData();
+        }
         break;
     }
 }
@@ -180,8 +192,8 @@ bool CSSFontFace::UnicodeRangeSet::intersectsWith(const String& text) const
 {
     if (text.isEmpty())
         return false;
-    if (m_ranges.isEmpty())
-        return true; // Empty UnicodeRangeSet represents the whole code space.
+    if (isEntireRange())
+        return true;
 
     // FIXME: This takes O(text.length() * m_ranges.size()) time. It would be
     // better to make m_ranges sorted and use binary search.