initial checkin for experimenting

src/core/SkCanvasDrawable.cpp

Index: src/core/SkCanvasDrawable.cpp
diff --git a/src/core/SkCanvasDrawable.cpp b/src/core/SkCanvasDrawable.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..7c01738dd60d74b0a4a8c41b544688a5b9614af6
--- /dev/null
+++ b/src/core/SkCanvasDrawable.cpp
@@ -0,0 +1,50 @@
+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkCanvas.h"
+#include "SkCanvasDrawable.h"
+#include "SkThread.h"
+
+static int32_t next_generation_id() {
+    static int32_t gCanvasDrawableGenerationID;
+
+    // do a loop in case our global wraps around, as we never want to
+    // return a 0
+    int32_t genID;
+    do {
+        genID = sk_atomic_inc(&gCanvasDrawableGenerationID) + 1;
+    } while (0 == genID);
+    return genID;
+}
+
+SkCanvasDrawable::SkCanvasDrawable() : fGenerationID(0) {}
+
+void SkCanvasDrawable::draw(SkCanvas* canvas) {
+    SkAutoCanvasRestore acr(canvas, true);
+    this->onDraw(canvas);
+}
+
+uint32_t SkCanvasDrawable::getGenerationID() {
+    if (0 == fGenerationID) {
+        fGenerationID = next_generation_id();
+    }
+    return fGenerationID;
+}
+
+bool SkCanvasDrawable::getBounds(SkRect* boundsPtr) {
+    SkRect bounds;
+    if (!boundsPtr) {
+        boundsPtr = &bounds;
+    }
+    return this->onGetBounds(boundsPtr);
+}
+
+void SkCanvasDrawable::notifyDrawingChanged() {
+    fGenerationID = 0;
+}
+
+