WebCrypto: Add SHA-1 support to crypto.subtle.digest().

LayoutTests/crypto/digest-expected.txt

+Tests cypto.subtle.digest.
+
+On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
+
+
+SHA1 of [] -- with empty process()
+    = [da 39 a3 ee 5e 6b 4b 0d 32 55 bf ef 95 60 18 90 af d8 07 09]
+SHA1 of [] -- without calling process()
+    = [da 39 a3 ee 5e 6b 4b 0d 32 55 bf ef 95 60 18 90 af d8 07 09]
+SHA1 of [0x0]
+    = [5b a9 3c 9d b0 cf f9 3f 52 b5 21 d7 42 0e 43 f6 ed a2 78 4f]
+SHA1 of [0x0] -- as an ArrayBuffer
+    = [5b a9 3c 9d b0 cf f9 3f 52 b5 21 d7 42 0e 43 f6 ed a2 78 4f]
+SHA1 of [0, 1, 2, 3, 4, 5] -- multipart
+    = [86 84 60 d9 8d 09 d8 bb b9 3d 7b 6c dd 15 cc 7f be c6 76 b9]
+Call process() after finish()
+    = [da 39 a3 ee 5e 6b 4b 0d 32 55 bf ef 95 60 18 90 af d8 07 09]
+abort()
+    rejected with value of null
+abort() and then abort()
+    rejected with value of null
+process() and then abort()
+    rejected with value of null
+finish() and then abort()
+    = [da 39 a3 ee 5e 6b 4b 0d 32 55 bf ef 95 60 18 90 af d8 07 09]
+finish() and then process()
+    = [da 39 a3 ee 5e 6b 4b 0d 32 55 bf ef 95 60 18 90 af d8 07 09]
+finish() and then abort()
+    = [da 39 a3 ee 5e 6b 4b 0d 32 55 bf ef 95 60 18 90 af d8 07 09]
+finish() and then finish()
+    = [da 39 a3 ee 5e 6b 4b 0d 32 55 bf ef 95 60 18 90 af d8 07 09]
+PASS op.process(null) threw exception TypeError: Type error.
+PASS op.process() threw exception TypeError: Not enough arguments.
+PASS op.process(-1) threw exception TypeError: Type error.
+PASS successfullyParsed is true
+
+TEST COMPLETE
+