Fix crash with SkDeferredCanvas+SkSurface integration with in order draw buffer.

tests/DeferredCanvasTest.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 "Test.h"
 #include "SkBitmap.h"
 #include "SkBitmapProcShader.h"
@@ skipping 509 matching lines @@
     REPORTER_ASSERT(reporter, image1->uniqueID() == image2->uniqueID());
     // Now we obtain a snpshot via the deferred canvas, which triggers a flush.
     // Because there is a pending clear, this will generate a different image.
     SkImage* image3 = canvas.newImageSnapshot();
     SkAutoTUnref<SkImage> aur_i3(image3);
     REPORTER_ASSERT(reporter, image1->uniqueID() != image3->uniqueID());
     // Verify that backing store is now a different buffer because of copy on
     // write
     PixelPtr pixels2 = getSurfacePixelPtr(surface, useGpu);
     REPORTER_ASSERT(reporter, pixels1 != pixels2);
-    canvas.clear(SK_ColorWHITE);
-    canvas.flush();
+    // Verify copy-on write with a draw operation that gets deferred by
+    // the in order draw buffer.
+    SkPaint paint;
+    canvas.drawPaint(paint);
+    SkImage* image4 = canvas.newImageSnapshot();  // implicit flush
+    SkAutoTUnref<SkImage> aur_i4(image4);
+    REPORTER_ASSERT(reporter, image4->uniqueID() != image3->uniqueID());
     PixelPtr pixels3 = getSurfacePixelPtr(surface, useGpu);
+    REPORTER_ASSERT(reporter, pixels2 != pixels3);
     // Verify that a direct canvas flush with a pending draw does not trigger
     // a copy on write when the surface is not sharing its buffer with an
     // SkImage.
-    canvas.clear(SK_ColorBLACK);
+    canvas.clear(SK_ColorWHITE);
     canvas.flush();
     PixelPtr pixels4 = getSurfacePixelPtr(surface, useGpu);
-    REPORTER_ASSERT(reporter, pixels3 == pixels4);
+    canvas.drawPaint(paint);
+    canvas.flush();
+    PixelPtr pixels5 = getSurfacePixelPtr(surface, useGpu);
+    REPORTER_ASSERT(reporter, pixels4 == pixels5);
 }
 
 static void TestDeferredCanvas(skiatest::Reporter* reporter, GrContextFactory* factory) {
     TestDeferredCanvasBitmapAccess(reporter);
     TestDeferredCanvasFlush(reporter);
     TestDeferredCanvasFreshFrame(reporter);
     TestDeferredCanvasMemoryLimit(reporter);
     TestDeferredCanvasBitmapCaching(reporter);
     TestDeferredCanvasSkip(reporter);
     TestDeferredCanvasBitmapShaderNoLeak(reporter);
     TestDeferredCanvasBitmapSizeThreshold(reporter);
     TestDeferredCanvasSurface(reporter, NULL);
     if (NULL != factory) {
         TestDeferredCanvasSurface(reporter, factory);
     }
 }
 
 #include "TestClassDef.h"
 DEFINE_GPUTESTCLASS("DeferredCanvas", TestDeferredCanvasClass, TestDeferredCanvas)