Clamp the max size of fonts used by skia/chrome canvas.

app/gfx/font.h

 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef APP_GFX_FONT_H_
 #define APP_GFX_FONT_H_
 
 #include "build/build_config.h"
 
 #include <string>
@@ skipping 201 matching lines @@
   explicit Font(SkTypeface* typeface, const std::wstring& name,
                 int size, int style);
   // Calculate and cache the font metrics.
   void calculateMetrics();
   // Make |this| a copy of |other|.
   void CopyFont(const Font& other);
 
   // The default font, used for the default constructor.
   static Font* default_font_;
 
+  // Return the scale factor for fonts that account for DPI.  We clamp the
+  // max DPI to prevent large fonts from overflowing UI elements.
+  static float GetPangoScaleFactor();
+
   // The average width of a character, initialized and cached if needed.
   double avg_width() const;
 
   // Potentially slow call to get pango metrics (avg width, underline info).
   void InitPangoMetrics();
 
   // These two both point to the same SkTypeface. We use the SkAutoUnref to
   // handle the reference counting, but without @typeface_ we would have to
   // cast the SkRefCnt from @typeface_helper_ every time.
   scoped_ptr<SkAutoUnref> typeface_helper_;
@@ skipping 29 matching lines @@
   int height_;
   int ascent_;
   int avg_width_;
 #endif
 
 };
 
 }  // namespace gfx
 
 #endif  // APP_GFX_FONT_H_