DM: go back to memcmp for BitmapsEqual

dm/DMUtil.cpp

Index: dm/DMUtil.cpp
diff --git a/dm/DMUtil.cpp b/dm/DMUtil.cpp
index d7d6691550b2113b4991d157c68d9155f8a7e453..f142d47dda23f506b7fcc2b546ca2281fcacc256 100644
--- a/dm/DMUtil.cpp
+++ b/dm/DMUtil.cpp
@@ -84,7 +84,11 @@ unsigned MaxComponentDifference(const SkBitmap& a, const SkBitmap& b) {
 }
 
 bool BitmapsEqual(const SkBitmap& a, const SkBitmap& b) {
-    return a.info() == b.info() && 0 == MaxComponentDifference(a, b);
+    if (a.info() != b.info()) {
+        return false;
+    }
+    const SkAutoLockPixels lockA(a), lockB(b);
+    return 0 == memcmp(a.getPixels(), b.getPixels(), a.getSize());
 }
 
 }  // namespace DM