Non-SFI NaCl: Allow CLOCK_SYSTEM_TRACE on Chrome OS

components/nacl/loader/nonsfi/nonsfi_sandbox.cc

Index: components/nacl/loader/nonsfi/nonsfi_sandbox.cc
diff --git a/components/nacl/loader/nonsfi/nonsfi_sandbox.cc b/components/nacl/loader/nonsfi/nonsfi_sandbox.cc
index 7ffb20e68b16160997ee7190b612eaaad7b08a6f..f22f4a467bc8cb951f159bc3120f44c414692edf 100644
--- a/components/nacl/loader/nonsfi/nonsfi_sandbox.cc
+++ b/components/nacl/loader/nonsfi/nonsfi_sandbox.cc
@@ -80,19 +80,26 @@ ErrorCode RestrictClockID(SandboxBPF* sb) {
   // returned by {clock,pthread}_getcpuclockid), which can leak information
   // about the state of the host OS.
   COMPILE_ASSERT(4 == sizeof(clockid_t), clockid_is_not_32bit);
-  return sb->Cond(0, ErrorCode::TP_32BIT,
-                  ErrorCode::OP_EQUAL, CLOCK_MONOTONIC,
-                  ErrorCode(ErrorCode::ERR_ALLOWED),
-         sb->Cond(0, ErrorCode::TP_32BIT,
-                  ErrorCode::OP_EQUAL, CLOCK_PROCESS_CPUTIME_ID,
-                  ErrorCode(ErrorCode::ERR_ALLOWED),
-         sb->Cond(0, ErrorCode::TP_32BIT,
-                  ErrorCode::OP_EQUAL, CLOCK_REALTIME,
-                  ErrorCode(ErrorCode::ERR_ALLOWED),
-         sb->Cond(0, ErrorCode::TP_32BIT,
-                  ErrorCode::OP_EQUAL, CLOCK_THREAD_CPUTIME_ID,
-                  ErrorCode(ErrorCode::ERR_ALLOWED),
-         sb->Trap(sandbox::CrashSIGSYS_Handler, NULL)))));
+  ErrorCode result = sb->Cond(0, ErrorCode::TP_32BIT,
+                              ErrorCode::OP_EQUAL, CLOCK_MONOTONIC,
+                              ErrorCode(ErrorCode::ERR_ALLOWED),
+                     sb->Cond(0, ErrorCode::TP_32BIT,
+                              ErrorCode::OP_EQUAL, CLOCK_PROCESS_CPUTIME_ID,
+                              ErrorCode(ErrorCode::ERR_ALLOWED),
+                     sb->Cond(0, ErrorCode::TP_32BIT,
+                              ErrorCode::OP_EQUAL, CLOCK_REALTIME,
+                              ErrorCode(ErrorCode::ERR_ALLOWED),
+                     sb->Cond(0, ErrorCode::TP_32BIT,
+                              ErrorCode::OP_EQUAL, CLOCK_THREAD_CPUTIME_ID,
+                              ErrorCode(ErrorCode::ERR_ALLOWED),
+                     sb->Trap(sandbox::CrashSIGSYS_Handler, NULL)))));
+#if defined(OS_CHROMEOS)
+  // Allow the special clock for Chrome OS used by Chrome tracing.
+  result = sb->Cond(0, ErrorCode::TP_32BIT,
+                    ErrorCode::OP_EQUAL, CLOCK_SYSTEM_TRACE,
+                    ErrorCode(ErrorCode::ERR_ALLOWED), result);
+#endif
+  return result;
 }
 
 ErrorCode RestrictClone(SandboxBPF* sb) {