Fix error handling in DirectWrite with tiny text.

src/ports/SkScalerContext_win_dw.h

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkScalarContext_win_dw_DEFINED
 #define SkScalarContext_win_dw_DEFINED
 
@@ skipping 19 matching lines @@
     virtual void generateMetrics(SkGlyph* glyph) SK_OVERRIDE;
     virtual void generateImage(const SkGlyph& glyph) SK_OVERRIDE;
     virtual void generatePath(const SkGlyph& glyph, SkPath* path) SK_OVERRIDE;
     virtual void generateFontMetrics(SkPaint::FontMetrics*) SK_OVERRIDE;
 
 private:
     const void* drawDWMask(const SkGlyph& glyph,
                            DWRITE_RENDERING_MODE renderingMode,
                            DWRITE_TEXTURE_TYPE textureType);
 
-    void getBoundingBox(SkGlyph* glyph,
-                        DWRITE_RENDERING_MODE renderingMode,
-                        DWRITE_TEXTURE_TYPE textureType,
-                        RECT* bbox);
+    HRESULT getBoundingBox(SkGlyph* glyph,
+                           DWRITE_RENDERING_MODE renderingMode,
+                           DWRITE_TEXTURE_TYPE textureType,
+                           RECT* bbox);
 
     SkTDArray<uint8_t> fBits;
     /** The total matrix without the text height scale. */
     SkMatrix fSkXform;
     /** The total matrix without the text height scale. */
     DWRITE_MATRIX fXform;
     /** The non-rotational part of total matrix without the text height scale.
      *  This is used to find the magnitude of gdi compatible advances.
      */
     DWRITE_MATRIX fGsA;
     /** The inverse of the rotational part of the total matrix.
      *  This is used to find the direction of gdi compatible advances.
      */
     SkMatrix fG_inv;
     /** The text size to render with. */
     SkScalar fTextSizeRender;
     /** The text size to measure with. */
     SkScalar fTextSizeMeasure;
     SkAutoTUnref<DWriteFontTypeface> fTypeface;
     int fGlyphCount;
     DWRITE_RENDERING_MODE fRenderingMode;
     DWRITE_TEXTURE_TYPE fTextureType;
     DWRITE_MEASURING_MODE fMeasuringMode;
 };
 
 #endif