add SkCanvas constructor that explicitly creates no_config with dimensions

src/utils/SkDumpCanvas.cpp

Index: src/utils/SkDumpCanvas.cpp
diff --git a/src/utils/SkDumpCanvas.cpp b/src/utils/SkDumpCanvas.cpp
index dabf0d79890ee0439b1a292a1e7adcae82965391..5f3a572ab92ee1c95cb9c5e44645df27d4ca8af4 100644
--- a/src/utils/SkDumpCanvas.cpp
+++ b/src/utils/SkDumpCanvas.cpp
@@ -163,15 +163,9 @@ static void toString(const void* text, size_t byteLen, SkPaint::TextEncoding enc
 
 ///////////////////////////////////////////////////////////////////////////////
 
-static SkBitmap make_wideopen_bm() {
-    static const int WIDE_OPEN = 16384;
+#define WIDE_OPEN   16384
 
-    SkBitmap bm;
-    bm.setConfig(SkBitmap::kNo_Config, WIDE_OPEN, WIDE_OPEN);
-    return bm;
-}
-
-SkDumpCanvas::SkDumpCanvas(Dumper* dumper) : INHERITED(make_wideopen_bm()) {
+SkDumpCanvas::SkDumpCanvas(Dumper* dumper) : INHERITED(WIDE_OPEN, WIDE_OPEN) {
     fNestLevel = 0;
     SkSafeRef(dumper);
     fDumper = dumper;