First pass at Comment API

include/core/SkCanvas.h

Index: include/core/SkCanvas.h
===================================================================
--- include/core/SkCanvas.h	(revision 8806)
+++ include/core/SkCanvas.h	(working copy)
@@ -847,6 +847,14 @@
      */
     virtual void drawData(const void* data, size_t length);
 
+    /** Add comments. beginGroup/endGroup open/close a new group. Each
+        comment added via addComment is notionally attached to its enclosing 
+        group. Top-level comments simply belong to no group.
+     */
+    virtual void beginGroup(const char* description);
+    virtual void addComment(const char* kywd, const char* value);
+    virtual void endGroup();

[djsollen, 2013/04/24 13:01:55]

Perhaps beginCommentGroup and endCommentGroup would be more descriptive.

+
     //////////////////////////////////////////////////////////////////////////
 
     /** Get the current bounder object.
@@ -1129,4 +1137,29 @@
     int         fSaveCount;
 };
 
+/** Stack helper class to automatically open and close a comment block
+ */
+class SkAutoCommentBlock : SkNoncopyable {
+public:
+    SkAutoCommentBlock(SkCanvas* canvas, const char* description) {
+        this->init(canvas, description);
+    }
+
+    ~SkAutoCommentBlock() {
+        if (NULL != fCanvas) {
+            fCanvas->endGroup();
+        }
+    }
+
+private:
+    SkCanvas* fCanvas;
+
+    void init(SkCanvas* canvas, const char* description) {
+        fCanvas = canvas;
+        if (NULL != fCanvas) {
+            fCanvas->beginGroup(description);
+        }
+    }
+};
+
 #endif