SkTextBlob GPipe serialization.

Instead of relying on unrolling blobs in SkCanvas, serialize when
passing through a GPipe.

This is a prerequisite for pushing the blob draw op to the device.

R=mtklein@google.com, reed@google.com, robertphillips@google.com

Author: fmalita@chromium.org

Review URL: https://codereview.chromium.org/511783005
diff --git a/src/pipe/SkGPipeWrite.cpp b/src/pipe/SkGPipeWrite.cpp
index 32af81d..b5d2522 100644
--- a/src/pipe/SkGPipeWrite.cpp
+++ b/src/pipe/SkGPipeWrite.cpp
@@ -26,6 +26,7 @@
 #include "SkRRect.h"
 #include "SkShader.h"
 #include "SkStream.h"
+#include "SkTextBlob.h"
 #include "SkTSearch.h"
 #include "SkTypeface.h"
 #include "SkWriter32.h"
@@ -939,9 +940,22 @@
 
 void SkGPipeCanvas::onDrawTextBlob(const SkTextBlob* blob, SkScalar x, SkScalar y,
                                    const SkPaint& paint) {
-    // FIXME: blob serialization only supports SkWriteBuffers
-    //        -- convert to SkWriter32 to avoid unrolling?
-    this->INHERITED::onDrawTextBlob(blob, x, y, paint);
+    NOTIFY_SETUP(this);
+    this->writePaint(paint);
+
+    // FIXME: this is inefficient but avoids duplicating the blob serialization logic.
+    SkWriteBuffer blobBuffer;
+    blob->flatten(blobBuffer);
+
+    size_t size = sizeof(uint32_t) + 2 * sizeof(SkScalar) + blobBuffer.bytesWritten();
+    if (this->needOpBytes(size)) {
+        this->writeOp(kDrawTextBlob_DrawOp);
+        fWriter.writeScalar(x);
+        fWriter.writeScalar(y);
+        fWriter.write32(SkToU32(blobBuffer.bytesWritten()));
+        uint32_t* pad = fWriter.reservePad(blobBuffer.bytesWritten());
+        blobBuffer.writeToMemory(pad);
+    }
 }
 
 void SkGPipeCanvas::onDrawPicture(const SkPicture* picture, const SkMatrix* matrix,