use some helper Make functions to initialize SkImageInfo

tests/PixelRefTest.cpp

 #include "Test.h"
 #include "TestClassDef.h"
 
 #include "SkPixelRef.h"
 #include "SkMallocPixelRef.h"
 
 static void test_info(skiatest::Reporter* reporter) {
     static const struct {
         SkBitmap::Config    fConfig;
         SkAlphaType         fAlphaType;
@@ skipping 33 matching lines @@
 public:
     explicit TestListener(int* ptr) : fPtr(ptr) {}
     void onChange() SK_OVERRIDE { (*fPtr)++; }
 private:
     int* fPtr;
 };
 
 }  // namespace
 
 DEF_TEST(PixelRef_GenIDChange, r) {
-    SkImageInfo info = { 10, 10, kPMColor_SkColorType, kPremul_SkAlphaType };
+    SkImageInfo info = SkImageInfo::MakeN32Premul(10, 10);
 
     SkAutoTUnref<SkPixelRef> pixelRef(SkMallocPixelRef::NewAllocate(info, 0, NULL));
 
     // Register a listener.
     int count = 0;
     pixelRef->addGenIDChangeListener(SkNEW_ARGS(TestListener, (&count)));
     REPORTER_ASSERT(r, 0 == count);
 
     // No one has looked at our pixelRef's generation ID, so invalidating it doesn't make sense.
     // (An SkPixelRef tree falls in the forest but there's nobody around to hear it.  Do we care?)
@@ skipping 13 matching lines @@
     pixelRef->notifyPixelsChanged();
     REPORTER_ASSERT(r, 1 == count);
 
     // Quick check that NULL is safe.
     REPORTER_ASSERT(r, 0 != pixelRef->getGenerationID());
     pixelRef->addGenIDChangeListener(NULL);
     pixelRef->notifyPixelsChanged();
 
     test_info(r);
 }