Add factory class for generating various flavors of GrTextContext.

include/gpu/GrTextContext.h

 /*
  * Copyright 2010 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrTextContext_DEFINED
 #define GrTextContext_DEFINED
 
 #include "GrContext.h"
 #include "GrGlyph.h"
 #include "GrPaint.h"
 
 class GrContext;
 class GrDrawTarget;
 class GrFontScaler;
 
 /*
  * This class wraps the state for a single text render
  */
 class GrTextContext {
 public:
     virtual void drawPackedGlyph(GrGlyph::PackedID, GrFixed left, GrFixed top,
                                  GrFontScaler*) = 0;
 
 protected:
-    GrTextContext(GrContext*, const GrPaint&);
+    GrTextContext(GrContext*, const GrPaint&, const SkPaint&);
     virtual ~GrTextContext() {}
 
     GrPaint                fPaint;
+    SkPaint                fSkPaint;
     GrContext*             fContext;
     GrDrawTarget*          fDrawTarget;
 
     SkIRect                fClipRect;
 
 private:

[tfarina, 2014/01/21 23:49:45]

while here, remove this empty section?

 };
 
+class GrTextContextFactory {
+public:
+    virtual ~GrTextContextFactory() {}
+    virtual GrTextContext* Create(GrContext* context, const GrPaint& grPaint, 
+                          const SkPaint& skPaint) = 0;
+    virtual void Destroy(GrTextContext* textContext) = 0;
+};
+
+/*
+ * This class wraps the creation of a single text context

[bsalomon, 2014/01/21 20:46:17]

Maybe a little more clear in the comment that it isn't a factory for a singleton
text context but that it assumes there is at most one undestroyed text context
at any given time.

[jvanverth1, 2014/01/21 21:10:56]

Done.

+ */
+template <class TextContextClass>
+class GrTTextContextFactory : public GrTextContextFactory {
+public:
+    GrTTextContextFactory() {
+        fAllocation = malloc(sizeof(TextContextClass));

[bsalomon, 2014/01/21 20:46:17]

SkMalloc/SkFree

[jvanverth1, 2014/01/21 21:10:56]

Done.

+        fUsed = false;
+    }
+    
+    ~GrTTextContextFactory() {
+        SkASSERT(!fUsed);
+        free(fAllocation);
+    }
+
+    GrTextContext* Create(GrContext* context, const GrPaint& grPaint, 
+                          const SkPaint& skPaint) {
+        // add check for usePath here?
+        SkASSERT(!fUsed);
+        TextContextClass* obj = new(fAllocation) TextContextClass(context, grPaint, skPaint);
+        fUsed = true;
+        return obj;
+    }
+
+    void Destroy(GrTextContext* textContext) {
+        SkASSERT((void*)textContext == fAllocation);
+        SkASSERT(fUsed);
+        ((TextContextClass*)textContext)->~TextContextClass();
+        fUsed = false;
+    }
+
+private:
+    void* fAllocation;
+    bool  fUsed;
+};
+
 #endif