adding preabandon flag to DM

dm/DMSrcSink.cpp

 #include "DMSrcSink.h"
 #include "SamplePipeControllers.h"
 #include "SkCommonFlags.h"
 #include "SkDocument.h"
+#include "SkError.h"
 #include "SkMultiPictureDraw.h"
 #include "SkNullCanvas.h"
 #include "SkOSFile.h"
 #include "SkPictureRecorder.h"
 #include "SkRandom.h"
 #include "SkSVGCanvas.h"
 #include "SkStream.h"
 #include "SkXMLWriter.h"
 
 namespace DM {
@@ skipping 135 matching lines @@
     : fContextType(ct)
     , fGpuAPI(api)
     , fSampleCount(samples)
     , fUseDFText(dfText)
     , fThreaded(threaded) {}
 
 int GPUSink::enclave() const {
     return fThreaded ? kAnyThread_Enclave : kGPU_Enclave;
 }
 
+void PreAbandonGpuContextErrorHandler(SkError, void*) {}
+
 Error GPUSink::draw(const Src& src, SkBitmap* dst, SkWStream*, SkString* log) const {
     GrContextFactory factory;
     const SkISize size = src.size();
     const SkImageInfo info =
         SkImageInfo::Make(size.width(), size.height(), kN32_SkColorType, kPremul_SkAlphaType);
     SkAutoTUnref<SkSurface> surface(
             NewGpuSurface(&factory, fContextType, fGpuAPI, info, fSampleCount, fUseDFText));
     if (!surface) {
         return "Could not create a surface.";
     }
+    if (FLAGS_preAbandonGpuContext) {
+        SkSetErrorCallback(&PreAbandonGpuContextErrorHandler, NULL);
+        factory.abandonContexts();
+    }
     SkCanvas* canvas = surface->getCanvas();
     Error err = src.draw(canvas);
     if (!err.isEmpty()) {
         return err;
     }
     canvas->flush();
     if (FLAGS_gpuStats) {
         canvas->getGrContext()->dumpCacheStats(log);
         canvas->getGrContext()->dumpGpuStats(log);
     }
     dst->allocPixels(info);
-    canvas->readPixels(dst, 0,0);
+    canvas->readPixels(dst, 0, 0);
     if (FLAGS_abandonGpuContext) {
         factory.abandonContexts();
     }
     return "";
 }
 
 /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
 
 PDFSink::PDFSink() {}
 
@@ skipping 265 matching lines @@
             surfaces.unrefAll();
             return "";
         }
         SkISize size() const SK_OVERRIDE { return fSize; }
         Name name() const SK_OVERRIDE { sk_throw(); return ""; }  // No one should be calling this.
     } proxy(fW, fH, pic, src.size());
     return fSink->draw(proxy, bitmap, stream, log);
 }
 
 }  // namespace DM