Implement canvas's globalCompositeOperation lighter properly....

skia/effects/SkKernel33MaskFilter.cpp

Index: skia/effects/SkKernel33MaskFilter.cpp
===================================================================
--- skia/effects/SkKernel33MaskFilter.cpp	(revision 14480)
+++ skia/effects/SkKernel33MaskFilter.cpp	(working copy)
@@ -19,6 +19,9 @@
     
     dst->fRowBytes = dst->fBounds.width();
     size_t size = dst->computeImageSize();
+    if (0 == size) {
+        return false;   // too big to allocate, abort
+    }
     dst->fImage = SkMask::AllocImage(size);
     
     const int h = src.fBounds.height();