Remove some unnecessary refcount increments in WebCrypto's EC code.

components/webcrypto/algorithms/ecdh.cc

Index: components/webcrypto/algorithms/ecdh.cc
diff --git a/components/webcrypto/algorithms/ecdh.cc b/components/webcrypto/algorithms/ecdh.cc
index de82db439eda9585230b40bcef2df83b97973d1a..8afca5c2841359610bf960d1b39e6c70e64f8e5c 100644
--- a/components/webcrypto/algorithms/ecdh.cc
+++ b/components/webcrypto/algorithms/ecdh.cc
@@ -79,20 +79,17 @@ class EcdhImplementation : public EcAlgorithm {
       return Status::ErrorEcdhCurveMismatch();
     }
 
-    crypto::ScopedEC_KEY public_key_ec(
-        EVP_PKEY_get1_EC_KEY(GetEVP_PKEY(public_key)));
+    EC_KEY* public_key_ec = EVP_PKEY_get0_EC_KEY(GetEVP_PKEY(public_key));
 
-    const EC_POINT* public_key_point =
-        EC_KEY_get0_public_key(public_key_ec.get());
+    const EC_POINT* public_key_point = EC_KEY_get0_public_key(public_key_ec);
 
-    crypto::ScopedEC_KEY private_key_ec(
-        EVP_PKEY_get1_EC_KEY(GetEVP_PKEY(base_key)));
+    EC_KEY* private_key_ec = EVP_PKEY_get0_EC_KEY(GetEVP_PKEY(base_key));
 
     // The size of the shared secret is the field size in bytes (rounded up).
     // Note that, if rounding was required, the most significant bits of the
     // secret are zero. So for P-521, the maximum length is 528 bits, not 521.
-    int field_size_bytes = NumBitsToBytes(
-        EC_GROUP_get_degree(EC_KEY_get0_group(private_key_ec.get())));
+    int field_size_bytes =
+        NumBitsToBytes(EC_GROUP_get_degree(EC_KEY_get0_group(private_key_ec)));
 
     // If a desired key length was not specified, default to the field size
     // (rounded up to nearest byte).
@@ -115,7 +112,7 @@ class EcdhImplementation : public EcAlgorithm {
     derived_bytes->resize(NumBitsToBytes(length_bits));
 
     int result = ECDH_compute_key(derived_bytes->data(), derived_bytes->size(),
-                                  public_key_point, private_key_ec.get(), 0);
+                                  public_key_point, private_key_ec, 0);
     if (result < 0 || static_cast<size_t>(result) != derived_bytes->size())
       return Status::OperationError();