Change GrTextContext fallbacks to be a linked list chain.

src/gpu/GrTextContext.cpp

 /*
  * Copyright 2010 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrTextContext.h"
 #include "GrContext.h"
 
 #include "SkAutoKern.h"
 #include "SkGlyphCache.h"
 #include "GrFontScaler.h"
 
 GrTextContext::GrTextContext(GrContext* context, const SkDeviceProperties& properties) :
+                            fFallbackTextContext(NULL),
                             fContext(context), fDeviceProperties(properties), fDrawTarget(NULL) {
 }
 
+GrTextContext::~GrTextContext() {
+    SkDELETE(fFallbackTextContext);
+}
+
 void GrTextContext::init(const GrPaint& grPaint, const SkPaint& skPaint) {
     const GrClipData* clipData = fContext->getClip();
 
     SkRect devConservativeBound;
     clipData->fClipStack->getConservativeBounds(
                                      -clipData->fOrigin.fX,
                                      -clipData->fOrigin.fY,
                                      fContext->getRenderTarget()->width(),
                                      fContext->getRenderTarget()->height(),
                                      &devConservativeBound);
 
     devConservativeBound.roundOut(&fClipRect);
 
     fDrawTarget = fContext->getTextTarget();
 
     fPaint = grPaint;
     fSkPaint = skPaint;
 }
 
+bool GrTextContext::drawText(const GrPaint& paint, const SkPaint& skPaint,
+                             const char text[], size_t byteLength,
+                             SkScalar x, SkScalar y) {
+
+    GrTextContext* textContext = this;
+    do {
+        if (textContext->canDraw(skPaint)) {
+            textContext->onDrawText(paint, skPaint, text, byteLength, x, y);
+            return true;
+        }
+        textContext = textContext->fFallbackTextContext;
+    } while (textContext);
+
+    return false;
+}
+
+bool GrTextContext::drawPosText(const GrPaint& paint, const SkPaint& skPaint,
+                                const char text[], size_t byteLength,
+                                const SkScalar pos[], int scalarsPerPosition,
+                                const SkPoint& offset) {
+
+    GrTextContext* textContext = this;
+    do {
+        if (textContext->canDraw(skPaint)) {
+            textContext->onDrawPosText(paint, skPaint, text, byteLength, pos, scalarsPerPosition,
+                                     offset);
+            return true;
+        }
+        textContext = textContext->fFallbackTextContext;
+    } while (textContext);
+
+    return false;
+}
+
+
 //*** change to output positions?
 void GrTextContext::MeasureText(SkGlyphCache* cache, SkDrawCacheProc glyphCacheProc,
                                 const char text[], size_t byteLength, SkVector* stopVector) {
     SkFixed     x = 0, y = 0;
     const char* stop = text + byteLength;
 
     SkAutoKern  autokern;
 
     while (text < stop) {
         // don't need x, y here, since all subpixel variants will have the
@@ skipping 20 matching lines @@
     if (cache->getAuxProcData(GlyphCacheAuxProc, &auxData)) {
         scaler = (GrFontScaler*)auxData;
     }
     if (NULL == scaler) {
         scaler = SkNEW_ARGS(GrFontScaler, (cache));
         cache->setAuxProc(GlyphCacheAuxProc, scaler);
     }
 
     return scaler;
 }