further skiaserve image performance improvements

tools/debugger/SkDebugCanvas.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkCanvasPriv.h"
 #include "SkClipStack.h"
 #include "SkDebugCanvas.h"
@@ skipping 181 matching lines @@
     SkASSERT(!fCommandVector.isEmpty());
     SkASSERT(index < fCommandVector.count());
 
     int saveCount = canvas->save();
 
     SkRect windowRect = SkRect::MakeWH(SkIntToScalar(canvas->getBaseLayerSize().width()),
                                        SkIntToScalar(canvas->getBaseLayerSize().height()));
 
     bool pathOpsMode = getAllowSimplifyClip();
     canvas->setAllowSimplifyClip(pathOpsMode);
-    canvas->clear(SK_ColorTRANSPARENT);
+    canvas->clear(SK_ColorWHITE);
     canvas->resetMatrix();
     if (!windowRect.isEmpty()) {
         canvas->clipRect(windowRect, SkRegion::kReplace_Op);
     }
     this->applyUserTransform(canvas);
 
     if (fPaintFilterCanvas) {
         fPaintFilterCanvas->addCanvas(canvas);
         canvas = fPaintFilterCanvas.get();
     }
@@ skipping 431 matching lines @@
 }
 
 bool SkDebugCanvas::lastClipStackData(const SkPath& devPath) {
     if (fCalledAddStackData) {
         fClipStackData.appendf("<br>");
         addPathData(devPath, "pathOut");
         return true;
     }
     return false;
 }