Suppress memory error in webcrypto

BUG=348629
TBR=padolph@netflix.com

Review URL: https://codereview.chromium.org/183893040

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@255364 0039d316-1c4b-4281-b951-d872f2087c98

tools/valgrind/memcheck/suppressions.txt

@@ -6314,3 +6314,10 @@
    fun:_ZN3WTFL16threadEntryPointEPv
    fun:_ZN3WTFL19wtfThreadEntryPointEPv
 }
+{
+   bug_349939
+   Memcheck:Uninitialized
+   fun:_ZN4base9HexEncodeEPKvm
+   fun:_ZN7content9webcrypto12_GLOBAL__N_118ArrayBufferMatchesERKSt6vectorIhSaIhEERKN5blink14WebArrayBufferE
+   fun:_ZN7content9webcrypto53SharedCryptoTest_AesKwRawSymkeyUnwrapCorruptData_Test8TestBodyEv
+}