Revert of rename SkCanvasDrawable to SkDrawable, and make public

include/core/SkDrawable.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 SkDrawable_DEFINED
-#define SkDrawable_DEFINED
-
-#include "SkRefCnt.h"
-
-class SkCanvas;
-class SkPicture;
-struct SkRect;
-
-/**
- *  Base-class for objects that draw into SkCanvas.
- *
- *  The object has a generation ID, which is guaranteed to be unique across all drawables. To
- *  allow for clients of the drawable that may want to cache the results, the drawable must
- *  change its generation ID whenever its internal state changes such that it will draw differently.
- */
-class SkDrawable : public SkRefCnt {
-public:
-    SkDrawable();
-
-    /**
-     *  Draws into the specified content. The drawing sequence will be balanced upon return
-     *  (i.e. the saveLevel() on the canvas will match what it was when draw() was called,
-     *  and the current matrix and clip settings will not be changed.
-     */
-    void draw(SkCanvas*);
-
-    SkPicture* newPictureSnapshot();
-
-    /**
-     *  Return a unique value for this instance. If two calls to this return the same value,
-     *  it is presumed that calling the draw() method will render the same thing as well.
-     *
-     *  Subclasses that change their state should call notifyDrawingChanged() to ensure that
-     *  a new value will be returned the next time it is called.
-     */
-    uint32_t getGenerationID();
-
-    /**
-     *  Return the (conservative) bounds of what the drawable will draw. If the drawable can
-     *  change what it draws (e.g. animation or in response to some external change), then this
-     *  must return a bounds that is always valid for all possible states.
-     */
-    SkRect getBounds();
-
-    /**
-     *  Calling this invalidates the previous generation ID, and causes a new one to be computed
-     *  the next time getGenerationID() is called. Typically this is called by the object itself,
-     *  in response to its internal state changing.
-     */
-    void notifyDrawingChanged();
-
-protected:
-    virtual SkRect onGetBounds() = 0;
-    virtual void onDraw(SkCanvas*) = 0;
-    
-    /**
-     *  Default implementation calls onDraw() with a canvas that records into a picture. Subclasses
-     *  may override if they have a more efficient way to return a picture for the current state
-     *  of their drawable. Note: this picture must draw the same as what would be drawn from
-     *  onDraw().
-     */
-    virtual SkPicture* onNewPictureSnapshot();
-
-private:
-    int32_t fGenerationID;
-};
-
-#endif