[Downloads] Rework how hashes are calculated for download files.

crypto/secure_hash_unittest.cc

Index: crypto/secure_hash_unittest.cc
diff --git a/crypto/secure_hash_unittest.cc b/crypto/secure_hash_unittest.cc
index df0afa6248a3340b9586f77cc1c90d0848fbf213..0fab17b6b6a221c3b5b69767d59252cab53f7d8d 100644
--- a/crypto/secure_hash_unittest.cc
+++ b/crypto/secure_hash_unittest.cc
@@ -10,7 +10,6 @@
 #include <string>
 
 #include "base/memory/scoped_ptr.h"
-#include "base/pickle.h"
 #include "crypto/sha2.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ -38,40 +37,53 @@ TEST(SecureHashTest, TestUpdate) {
     EXPECT_EQ(expected3[i], static_cast<int>(output3[i]));
 }
 
-// Save the crypto state mid-stream, and create another instance with the
-// saved state.  Then feed the same data afterwards to both.
-// When done, both should have the same hash value.
-TEST(SecureHashTest, TestSerialization) {
+TEST(SecureHashTest, TestClone) {
   std::string input1(10001, 'a');  // 'a' repeated 10001 times
-  std::string input2(10001, 'b');  // 'b' repeated 10001 times
-  std::string input3(10001, 'c');  // 'c' repeated 10001 times
-  std::string input4(10001, 'd');  // 'd' repeated 10001 times
-  std::string input5(10001, 'e');  // 'e' repeated 10001 times
+  std::string input2(10001, 'd');  // 'd' repeated 10001 times
+
+  uint8_t expected_sha256_hash_of_input1[crypto::kSHA256Length] = {
+      0x0c, 0xab, 0x99, 0xa0, 0x58, 0x60, 0x0f, 0xfa, 0xad, 0x12, 0x92,
+      0xd0, 0xc5, 0x3c, 0x05, 0x48, 0xeb, 0xaf, 0x88, 0xdd, 0x1d, 0x01,
+      0x03, 0x03, 0x45, 0x70, 0x5f, 0x01, 0x8a, 0x81, 0x39, 0x09
+  };
+  uint8_t expected_sha256_hash_of_inputs1and2[crypto::kSHA256Length] = {
+      0x4c, 0x8e, 0x26, 0x5a, 0xc3, 0x85, 0x1f, 0x1f, 0xa5, 0x04, 0x1c,
+      0xc7, 0x88, 0x53, 0x1c, 0xc7, 0x80, 0x47, 0x15, 0xfb, 0x47, 0xff,
+      0x72, 0xb1, 0x28, 0x37, 0xb0, 0x4d, 0x6e, 0x22, 0x2e, 0x4d
+  };
 
   uint8_t output1[crypto::kSHA256Length];
   uint8_t output2[crypto::kSHA256Length];
+  uint8_t output3[crypto::kSHA256Length];
 
   scoped_ptr<crypto::SecureHash> ctx1(crypto::SecureHash::Create(
       crypto::SecureHash::SHA256));
-  scoped_ptr<crypto::SecureHash> ctx2(crypto::SecureHash::Create(
-      crypto::SecureHash::SHA256));
-  base::Pickle pickle;
   ctx1->Update(input1.data(), input1.size());
-  ctx1->Update(input2.data(), input2.size());
-  ctx1->Update(input3.data(), input3.size());
 
-  EXPECT_TRUE(ctx1->Serialize(&pickle));
-  ctx1->Update(input4.data(), input4.size());
-  ctx1->Update(input5.data(), input5.size());
+  scoped_ptr<crypto::SecureHash> ctx2(ctx1->Clone());
+  scoped_ptr<crypto::SecureHash> ctx3(ctx2->Clone());
+  // At this point, ctx1, ctx2, and ctx3 are all equivalent and represent the
+  // state after hashing input1.
 
+  // Updating ctx1 and ctx2 with input2 should produce equivalent results.
+  ctx1->Update(input2.data(), input2.size());
   ctx1->Finish(output1, sizeof(output1));
 
-  base::PickleIterator data_iterator(pickle);
-  EXPECT_TRUE(ctx2->Deserialize(&data_iterator));
-  ctx2->Update(input4.data(), input4.size());
-  ctx2->Update(input5.data(), input5.size());
-
+  ctx2->Update(input2.data(), input2.size());
   ctx2->Finish(output2, sizeof(output2));
 
   EXPECT_EQ(0, memcmp(output1, output2, crypto::kSHA256Length));
+  EXPECT_EQ(0, memcmp(output1, expected_sha256_hash_of_inputs1and2,
+                      crypto::kSHA256Length));
+
+  // Finish() ctx3, which should produce the hash of input1.
+  ctx3->Finish(&output3, sizeof(output3));
+  EXPECT_EQ(0, memcmp(output3, expected_sha256_hash_of_input1,
+                      crypto::kSHA256Length));
+}
+
+TEST(SecureHashTest, TestLength) {
+  scoped_ptr<crypto::SecureHash> ctx(
+      crypto::SecureHash::Create(crypto::SecureHash::SHA256));
+  EXPECT_EQ(crypto::kSHA256Length, ctx->GetHashLength());
 }