Make SkSHA1 and SkM5 use common SkDigestHash result type

gm/gmmain.cpp

Index: gm/gmmain.cpp
===================================================================
--- gm/gmmain.cpp	(revision 8685)
+++ gm/gmmain.cpp	(working copy)
@@ -714,7 +714,7 @@
                                              const char renderModeDescriptor[],
                                              bool addToJsonSummary) {
         ErrorCombination errors;
-        SkHashDigest actualBitmapHash;
+        SkUInt64HashDigest actualBitmapHash;
         // TODO(epoger): Better handling for error returned by ComputeDigest()?
         // For now, we just report a digest of 0 in error cases, like before.
         if (!SkBitmapHasher::ComputeDigest(actualBitmap, &actualBitmapHash)) {
@@ -768,7 +768,7 @@
      * depending on status.
      */
     void add_actual_results_to_json_summary(const char testName[],
-                                            const SkHashDigest& actualBitmapHash,
+                                            const SkUInt64HashDigest& actualBitmapHash,
                                             ErrorCombination result,
                                             bool ignoreFailure) {
         Json::Value actualResults;
@@ -864,7 +864,7 @@
         } else {
             // If we are running without expectations, we still want to
             // record the actual results.
-            SkHashDigest actualBitmapHash;
+            SkUInt64HashDigest actualBitmapHash;
             // TODO(epoger): Better handling for error returned by ComputeDigest()?
             // For now, we just report a digest of 0 in error cases, like before.
             if (!SkBitmapHasher::ComputeDigest(actualBitmap, &actualBitmapHash)) {