Add standalone drawText for GrTextContext.

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 "SkAutoKern.h"
+#include "SkGlyphCache.h"
+#include "SkGpuDevice.h"
 
 GrTextContext::GrTextContext(GrContext* context, const GrPaint& paint,
-                             const SkPaint& skPaint) : fPaint(paint), fSkPaint(skPaint) {
-    fContext = context;
+                             const SkPaint& skPaint, const SkDeviceProperties* properties) : 
+                            fContext(context), fPaint(paint), fSkPaint(skPaint),
+                            fDeviceProperties(properties) {
 
     const GrClipData* clipData = context->getClip();
 
     SkRect devConservativeBound;
     clipData->fClipStack->getConservativeBounds(
                                      -clipData->fOrigin.fX,
                                      -clipData->fOrigin.fY,
                                      context->getRenderTarget()->width(),
                                      context->getRenderTarget()->height(),
                                      &devConservativeBound);
 
     devConservativeBound.roundOut(&fClipRect);
 
-    fDrawTarget = fContext->getTextTarget();
+    fDrawTarget = context->getTextTarget();
 }
+
+//*** 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
+        // same advance
+        const SkGlyph& glyph = glyphCacheProc(cache, &text, 0, 0);
+        
+        x += autokern.adjust(glyph) + glyph.fAdvanceX;
+        y += glyph.fAdvanceY;
+    }
+    stopVector->set(SkFixedToScalar(x), SkFixedToScalar(y));
+    
+    SkASSERT(text == stop);
+}
+
+static void GlyphCacheAuxProc(void* data) {
+    GrFontScaler* scaler = (GrFontScaler*)data;
+    SkSafeUnref(scaler);
+}
+
+GrFontScaler* GrTextContext::GetGrFontScaler(SkGlyphCache* cache) {
+    void* auxData;
+    GrFontScaler* scaler = NULL;
+    
+    if (cache->getAuxProcData(GlyphCacheAuxProc, &auxData)) {
+        scaler = (GrFontScaler*)auxData;
+    }
+    if (NULL == scaler) {
+        scaler = SkNEW_ARGS(SkGrFontScaler, (cache));
+        cache->setAuxProc(GlyphCacheAuxProc, scaler);
+    }
+    
+    return scaler;
+}
+