First pass at Comment API

debugger/SkDebugCanvas.cpp

Index: debugger/SkDebugCanvas.cpp
===================================================================
--- debugger/SkDebugCanvas.cpp	(revision 8806)
+++ debugger/SkDebugCanvas.cpp	(working copy)
@@ -389,6 +389,18 @@
     addDrawCommand(new DrawData(data, length));
 }
 
+void SkDebugCanvas::beginGroup(const char* description) {
+    addDrawCommand(new BeginGroup(description));
+}
+
+void SkDebugCanvas::addComment(const char* kywd, const char* value) {
+    addDrawCommand(new Comment(kywd, value));
+}
+
+void SkDebugCanvas::endGroup() {
+    addDrawCommand(new EndGroup());
+}
+
 void SkDebugCanvas::drawOval(const SkRect& oval, const SkPaint& paint) {
     addDrawCommand(new DrawOval(oval, paint));
 }