Adding macro to enable changing SSL library (Part 1)

This changes the macro used to be USE_NSS_VERIFIER and modifies build
files to no longer assume iOS is using NSS.

BUG=591545

Review URL: https://codereview.chromium.org/1808963004

Cr-Commit-Position: refs/heads/master@{#382077}

1 files changed, 11 insertions, 1 deletions

diff --git a/ios/chrome/browser/ios_chrome_io_thread.mm b/ios/chrome/browser/ios_chrome_io_thread.mm
index 0fbdab0..4e76c5a 100644
--- a/ios/chrome/browser/ios_chrome_io_thread.mm
+++ b/ios/chrome/browser/ios_chrome_io_thread.mm
@@ -140,12 +140,18 @@ const char kNpnTrialDisabledGroupNamePrefix[] = "Disable";
 // Used for the "system" URLRequestContext.
 class SystemURLRequestContext : public net::URLRequestContext {
  public:
-  SystemURLRequestContext() { net::SetURLRequestContextForNSSHttpIO(this); }
+  SystemURLRequestContext() {
+#if defined(USE_NSS_VERIFIER)
+    net::SetURLRequestContextForNSSHttpIO(this);
+#endif
+  }
 
  private:
   ~SystemURLRequestContext() override {
     AssertNoURLRequests();
+#if defined(USE_NSS_VERIFIER)
     net::SetURLRequestContextForNSSHttpIO(nullptr);
+#endif
   }
 };
 
@@ -377,7 +383,9 @@ void IOSChromeIOThread::Init() {
   TRACE_EVENT0("startup", "IOSChromeIOThread::Init");
   DCHECK_CURRENTLY_ON(web::WebThread::IO);
 
+#if defined(USE_NSS_VERIFIER)
   net::SetMessageLoopForNSSHttpIO();
+#endif
 
   const base::CommandLine& command_line =
       *base::CommandLine::ForCurrentProcess();
@@ -474,7 +482,9 @@ void IOSChromeIOThread::Init() {
 }
 
 void IOSChromeIOThread::CleanUp() {
+#if defined(USE_NSS_VERIFIER)
   net::ShutdownNSSHttpIO();
+#endif
 
   system_url_request_context_getter_ = nullptr;