AU: Switch from SHA-1 to SHA-256 hash.

For hashing of images, expect a new "sha256" attribute in Omaha's updatecheck
response.

BUG=6580
TEST=unit tests, gmerged on device and updated with upgraded dev server

Change-Id: I122e21cd7edc74695cb81b2eee5ce70f152f5270

Review URL: http://codereview.chromium.org/3419018
diff --git a/omaha_hash_calculator_unittest.cc b/omaha_hash_calculator_unittest.cc
index 0ee3b80..d228f12 100644
--- a/omaha_hash_calculator_unittest.cc
+++ b/omaha_hash_calculator_unittest.cc
@@ -18,8 +18,8 @@
   calc.Update("hi", 2);
   calc.Finalize();
   // Generated by running this on a linux shell:
-  // $ echo -n hi | openssl sha1 -binary | openssl base64
-  EXPECT_EQ("witfkXg0JglCjW9RssWvTAveakI=", calc.hash());
+  // $ echo -n hi | openssl dgst -sha256 -binary | openssl base64
+  EXPECT_EQ("j0NDRmSPa5bfid2pAcUXaxCm2Dlh3TwayItZstwyeqQ=", calc.hash());
 }
 
 TEST(OmahaHashCalculatorTest, MultiUpdateTest) {
@@ -28,8 +28,8 @@
   calc.Update("i", 1);
   calc.Finalize();
   // Generated by running this on a linux shell:
-  // $ echo -n hi | openssl sha1 -binary | openssl base64
-  EXPECT_EQ("witfkXg0JglCjW9RssWvTAveakI=", calc.hash());
+  // $ echo -n hi | openssl dgst -sha256 -binary | openssl base64
+  EXPECT_EQ("j0NDRmSPa5bfid2pAcUXaxCm2Dlh3TwayItZstwyeqQ=", calc.hash());
 }
 
 TEST(OmahaHashCalculatorTest, BigTest) {
@@ -48,8 +48,8 @@
   // $ while [ $C -lt 1000000 ]; do
   //     echo -n $C
   //     let C=C+1
-  //   done | openssl sha1 -binary | openssl base64
-  EXPECT_EQ("qdNsMeRqzoEUu5/ABi+MGRli87s=", calc.hash());
+  //   done | openssl dgst -sha256 -binary | openssl base64
+  EXPECT_EQ("NZf8k6SPBkYMvhaX8YgzuMgbkLP1XZ+neM8K5wcSsf8=", calc.hash());
 }
 
 TEST(OmahaHashCalculatorTest, AbortTest) {