Switch SkAutoMalloc to SkAutoTMalloc to avoid cast

tests/CanvasTest.cpp

Index: tests/CanvasTest.cpp
diff --git a/tests/CanvasTest.cpp b/tests/CanvasTest.cpp
index 2ec25e4bab023b699107b57cf92f0957c2c26e31..87705dc7f5e00cd6efb52bbb9e5efa04a7915994 100644
--- a/tests/CanvasTest.cpp
+++ b/tests/CanvasTest.cpp
@@ -61,6 +61,7 @@
 #include "SkShader.h"
 #include "SkStream.h"
 #include "SkSurface.h"
+#include "SkTemplates.h"
 #include "SkTDArray.h"
 #include "Test.h"
 
@@ -635,8 +636,8 @@ static void test_newraster(skiatest::Reporter* reporter) {
     SkImageInfo info = SkImageInfo::MakeN32Premul(10, 10);
     const size_t minRowBytes = info.minRowBytes();
     const size_t size = info.getSafeSize(minRowBytes);
-    SkAutoMalloc storage(size);
-    SkPMColor* baseAddr = static_cast<SkPMColor*>(storage.get());
+    SkAutoTMalloc<SkPMColor> storage(size);
+    SkPMColor* baseAddr = storage.get();
     sk_bzero(baseAddr, size);
 
     SkCanvas* canvas = SkCanvas::NewRasterDirect(info, baseAddr, minRowBytes);