Handle getMemoryBase returning NULL in WriteTask.

dm/DMWriteTask.cpp

 #include "DMWriteTask.h"
 
 #include "DMUtil.h"
 #include "SkColorPriv.h"
 #include "SkCommonFlags.h"
 #include "SkData.h"
 #include "SkImageEncoder.h"
 #include "SkMD5.h"
 #include "SkMallocPixelRef.h"
 #include "SkOSFile.h"
@@ skipping 46 matching lines @@
     SkASSERT(fData.get());
     SkASSERT(fData->unique());
 }
 
 void WriteTask::makeDirOrFail(SkString dir) {
     if (!sk_mkdir(dir.c_str())) {
         this->fail();
     }
 }
 
-static SkString get_md5(const void* ptr, size_t len) {
-    SkMD5 hasher;
-    hasher.write(ptr, len);
+static SkString get_md5_string(SkMD5* hasher) {
     SkMD5::Digest digest;
-    hasher.finish(digest);
+    hasher->finish(digest);
 
     SkString md5;
     for (int i = 0; i < 16; i++) {
         md5.appendf("%02x", digest.data[i]);
     }
     return md5;
 }
 
+static SkString get_md5(const void* ptr, size_t len) {
+    SkMD5 hasher;
+    hasher.write(ptr, len);
+    return get_md5_string(&hasher);
+}
+
+static SkString get_md5(SkStreamAsset* stream) {
+    SkMD5 hasher;
+    hasher.writeStream(stream, stream->getLength());
+    return get_md5_string(&hasher);
+}
+
 struct JsonData {
     SkString name;            // E.g. "ninepatch-stretch", "desk-gws_skp"
     SkString config;          //      "gpu", "8888"
     SkString mode;            //      "direct", "default-tilegrid", "pipe"
     SkString sourceType;      //      "GM", "SKP"
     SkString md5;             // In ASCII, so 32 bytes long.
 };
 SkTArray<JsonData> gJsonData;
 SK_DECLARE_STATIC_MUTEX(gJsonDataLock);
 
 void WriteTask::draw() {
     SkString md5;
     {
         SkAutoLockPixels lock(fBitmap);
-        md5 = fData ? get_md5(fData->getMemoryBase(), fData->getLength())
+        md5 = fData ? get_md5(fData)
                     : get_md5(fBitmap.getPixels(), fBitmap.getSize());
     }
 
     SkASSERT(fSuffixes.count() > 0);
     SkString config = fSuffixes.back();
     SkString mode("direct");
     if (fSuffixes.count() > 1) {
         mode = fSuffixes.fromBack(1);
     }
 
@@ skipping 87 matching lines @@
         }
     }
 
     SkString path = SkOSPath::Join(FLAGS_writePath[0], "dm.json");
     SkFILEWStream stream(path.c_str());
     stream.writeText(Json::StyledWriter().write(root).c_str());
     stream.flush();
 }
 
 }  // namespace DM