Revert "Refactor Update operation to return amount of input consumed."

This reverts commit 125febcb5d1888fa82e8c2eb307513598a537999.
diff --git a/ecdsa_operation.cpp b/ecdsa_operation.cpp
index aa41095..3987394 100644
--- a/ecdsa_operation.cpp
+++ b/ecdsa_operation.cpp
@@ -26,28 +26,24 @@
         EC_KEY_free(ecdsa_key_);
 }
 
-keymaster_error_t EcdsaOperation::Update(const Buffer& input, Buffer* /* output */,
-                                         size_t* input_consumed) {
-    assert(input_consumed);
+keymaster_error_t EcdsaOperation::Update(const Buffer& input, Buffer* /* output */) {
     switch (purpose()) {
     default:
         return KM_ERROR_UNIMPLEMENTED;
     case KM_PURPOSE_SIGN:
     case KM_PURPOSE_VERIFY:
-        return StoreData(input, input_consumed);
+        return StoreData(input);
     }
 }
 
-keymaster_error_t EcdsaOperation::StoreData(const Buffer& input, size_t* input_consumed) {
+keymaster_error_t EcdsaOperation::StoreData(const Buffer& input) {
     if (!data_.reserve(data_.available_read() + input.available_read()) ||
         !data_.write(input.peek_read(), input.available_read()))
         return KM_ERROR_MEMORY_ALLOCATION_FAILED;
-    *input_consumed = input.available_read();
     return KM_ERROR_OK;
 }
 
 keymaster_error_t EcdsaSignOperation::Finish(const Buffer& /* signature */, Buffer* output) {
-    assert(output);
     output->Reinitialize(ECDSA_size(ecdsa_key_));
     unsigned int siglen;
     if (!ECDSA_sign(0 /* type -- ignored */, data_.peek_read(), data_.available_read(),