First pass at Comment API

src/core/SkPictureRecord.cpp

Index: src/core/SkPictureRecord.cpp
===================================================================
--- src/core/SkPictureRecord.cpp	(revision 9288)
+++ src/core/SkPictureRecord.cpp	(working copy)
@@ -106,6 +106,9 @@
         0,  // SKEW - no paint
         0,  // TRANSLATE - no paint
         0,  // NOOP - no paint
+        0,  // BEGIN_GROUP - no paint
+        0,  // COMMENT - no paint
+        0,  // END_GROUP - no paint
     };
 
     SkASSERT(sizeof(gPaintOffsets) == LAST_DRAWTYPE_ENUM + 1);
@@ -1276,6 +1279,33 @@
     validate(initialOffset, size);
 }
 
+void SkPictureRecord::beginCommentGroup(const char* description) {
+    // op/size + length of string + \0 terminated chars
+    int length = strlen(description);
+    uint32_t size = 2 * kUInt32Size + SkAlign4(length + 1);
+    uint32_t initialOffset = this->addDraw(BEGIN_COMMENT_GROUP, &size);
+    fWriter.writeString(description, length);
+    validate(initialOffset, size);
+}
+
+void SkPictureRecord::addComment(const char* kywd, const char* value) {
+    // op/size + 2x length of string + 2x \0 terminated chars
+    int kywdLen = strlen(kywd);
+    int valueLen = strlen(value);
+    uint32_t size = 3 * kUInt32Size + SkAlign4(kywdLen + 1) + SkAlign4(valueLen + 1);
+    uint32_t initialOffset = this->addDraw(COMMENT, &size);
+    fWriter.writeString(kywd, kywdLen);
+    fWriter.writeString(value, valueLen);
+    validate(initialOffset, size);
+}
+
+void SkPictureRecord::endCommentGroup() {
+    // op/size
+    uint32_t size = 1 * kUInt32Size;
+    uint32_t initialOffset = this->addDraw(END_COMMENT_GROUP, &size);
+    validate(initialOffset, size);
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 
 void SkPictureRecord::addBitmap(const SkBitmap& bitmap) {