Add fallback code for TextContexts that don't support all features

src/gpu/GrDistanceFieldTextContext.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrDistanceFieldTextContext.h"
 #include "GrAtlas.h"
 #include "GrDrawTarget.h"
 #include "GrFontScaler.h"
 #include "SkGlyphCache.h"
 #include "GrIndexBuffer.h"
 #include "GrTextStrike.h"
 #include "GrTextStrike_impl.h"
+#include "SkDraw.h"
 #include "SkGpuDevice.h"
 #include "SkPath.h"
 #include "SkRTConf.h"
 #include "SkStrokeRec.h"
 #include "effects/GrDistanceFieldTextureEffect.h"
 
 static const int kGlyphCoordsAttributeIndex = 1;
 
 static const int kBaseDFFontSize = 32;
 
 SK_CONF_DECLARE(bool, c_DumpFontCache, "gpu.dumpFontCache", false,
                 "Dump the contents of the font cache before every purge.");
 
+bool GrDistanceFieldTextContext::CanDraw(const SkPaint& paint, const SkMatrix& ctm) {
+    return !paint.getRasterizer() && !paint.getMaskFilter() &&
+           paint.getStyle() == SkPaint::kFill_Style &&
+           !SkDraw::ShouldDrawTextAsPaths(paint, ctm);
+}
+
 GrDistanceFieldTextContext::GrDistanceFieldTextContext(GrContext* context,
                                                        const GrPaint& grPaint,
                                                        const SkPaint& skPaint,
                                                        const SkDeviceProperties& properties)
                                             : GrTextContext(context, grPaint, skPaint, properties) {
     fStrike = NULL;
 
     fCurrTexture = NULL;
     fCurrVertex = 0;
 
@@ skipping 368 matching lines @@
                                       SkScalarToFixed(x) - (glyph.fAdvanceX >> alignShift)
                                         + SK_FixedHalf, //d1g.fHalfSampleX,
                                       SkScalarToFixed(y) - (glyph.fAdvanceY >> alignShift)
                                         + SK_FixedHalf, //d1g.fHalfSampleY,
                                       fontScaler);
             }
             pos += scalarsPerPosition;
         }
     }
 }