Improvements to TestBase

This patch merges some features that were added to TestBase in
http://go/wvgerrit/92349 in the Widevine Repo. Certain parameters to
TestBase that could have been const but weren't now are. The caller to
Initialize() can now specify additional, platform-specific help text to
be displayed after the generic help text. And some missing headers were
added to test_base.h.

The Android code does not yet take advantage of any of this, but it
could in the future.

Bug: 145013234
Test: Android Unit Tests
Change-Id: I3c54532a39641622d454256b25979ad89727d43f

libwvdrmengine/cdm/core/test/test_base.cpp

@@ -32,7 +32,7 @@ using wvcdm::metrics::EngineMetrics;
 
 namespace wvcdm {
 namespace {
-void show_menu(char* prog_name) {
+void show_menu(const char* prog_name, const std::string& extra_help_text) {
   std::cout << std::endl;
   std::cout << "usage: " << prog_name << " [options]" << std::endl << std::endl;
   std::cout << "  enclose multiple arguments in '' when using adb shell"
@@ -97,6 +97,8 @@ void show_menu(char* prog_name) {
       << "    configure the provisioning server url, please include http[s]"
       << "    in the url" << std::endl
       << std::endl;
+
+  std::cout << extra_help_text << std::endl;
 }
 
 /*
@@ -393,7 +395,8 @@ void WvCdmTestBase::EnsureProvisioned() {
   ASSERT_EQ(NO_ERROR, cdm_engine.CloseSession(session_id));
 }
 
-bool WvCdmTestBase::Initialize(int argc, char** argv) {
+bool WvCdmTestBase::Initialize(int argc, const char* const argv[],
+                               const std::string& extra_help_text) {
   Properties::Init();
   bool is_cast_receiver = false;
   bool force_load_test_keybox = false;  // TODO(fredgc): obsolete. remove.
@@ -454,7 +457,7 @@ bool WvCdmTestBase::Initialize(int argc, char** argv) {
   }
 
   if (show_usage) {
-    show_menu(argv[0]);
+    show_menu(argv[0], extra_help_text);
     return false;
   }