Replaced NULL with nullptr in Android CDM.

[ Merge of http://go/wvgerrit/85503 ]

Replacing a few instances of C's NULL with C++'s nullptr in some of the
smaller sub-directories in the CDM.

Note that clang-format has performed additional changes to some of the
test files that have not yet been formatted.

Bug: 120602075
Test: Android unittest
Change-Id: I926135ed4b85e9d2d58a014b4a62098b0cb7a373

libwvdrmengine/cdm/test/wv_cdm_metrics_test.cpp

@@ -101,8 +101,8 @@ TEST_F(WvContentDecryptionModuleMetricsTest, EngineAndSessionMetrics) {
   // Openning the session will fail with NEEDS_PROVISIONING error. But it will
   // still create some session-level stats.
   EXPECT_EQ(CdmResponseType::NEED_PROVISIONING,
-            decryptor_.OpenSession(key_system, NULL,
-                                   kDefaultCdmIdentifier, NULL, &session_id));
+            decryptor_.OpenSession(key_system, nullptr, kDefaultCdmIdentifier,
+                                   nullptr, &session_id));
 
   drm_metrics::WvCdmMetrics metrics;
   ASSERT_EQ(wvcdm::NO_ERROR,
@@ -155,8 +155,8 @@ TEST_F(WvContentDecryptionModuleMetricsTest,
     // each identifier.
     for (int j = 0; j <= i; j ++) {
       EXPECT_EQ(CdmResponseType::NEED_PROVISIONING,
-                decryptor_.OpenSession(key_system, NULL,
-                                       identifiers[i], NULL, &session_id));
+                decryptor_.OpenSession(key_system, nullptr, identifiers[i],
+                                       nullptr, &session_id));
     }
   }