Fix crash with --use-gl=egl on Linux.

content/common/sandbox_linux/bpf_gpu_policy_linux.cc

Index: content/common/sandbox_linux/bpf_gpu_policy_linux.cc
diff --git a/content/common/sandbox_linux/bpf_gpu_policy_linux.cc b/content/common/sandbox_linux/bpf_gpu_policy_linux.cc
index 74f9871fc30a92c8cd3abca5527c5ebb896937d1..83e07acb3ee86f45e1a719bcf497e39d3ce408fb 100644
--- a/content/common/sandbox_linux/bpf_gpu_policy_linux.cc
+++ b/content/common/sandbox_linux/bpf_gpu_policy_linux.cc
@@ -169,14 +169,29 @@ bool UpdateProcessTypeAndEnableSandbox(sandbox::bpf_dsl::SandboxBPFDSLPolicy* (
 
 }  // namespace
 
-GpuProcessPolicy::GpuProcessPolicy() : broker_process_(NULL) {}
+GpuProcessPolicy::GpuProcessPolicy() : GpuProcessPolicy(false) {
+}
+
+GpuProcessPolicy::GpuProcessPolicy(bool allow_mincore)
+    : broker_process_(NULL), allow_mincore_(allow_mincore) {
+}
 
 GpuProcessPolicy::~GpuProcessPolicy() {}
 
 // Main policy for x86_64/i386. Extended by CrosArmGpuProcessPolicy.
 ResultExpr GpuProcessPolicy::EvaluateSyscall(int sysno) const {
   switch (sysno) {
+    case __NR_access:

[Jorge Lucangeli Obes, 2014/10/20 19:52:59]

While we order things mostly alphabetically, we don't follow the suggestion when
it makes the code more prone to breakage. The reason why __NR_access was below
is because it's got the same behaviour as open and openat, and if we ever change
it we want to change it for the three syscalls. I think it would be better to
keep it below. Sorry about that.

+      DCHECK(broker_process_);
+      return Trap(GpuSIGSYS_Handler, broker_process_);
     case __NR_ioctl:
+      return Allow();
+    case __NR_mincore:
+      if (allow_mincore_) {
+        return Allow();
+      } else {
+        return SandboxBPFBasePolicy::EvaluateSyscall(sysno);
+      }
 #if defined(__i386__) || defined(__x86_64__) || defined(__mips__)
     // The Nvidia driver uses flags not in the baseline policy
     // (MAP_LOCKED | MAP_EXECUTABLE | MAP_32BIT)
@@ -188,7 +203,6 @@ ResultExpr GpuProcessPolicy::EvaluateSyscall(int sysno) const {
     // TODO(jln): restrict prctl.
     case __NR_prctl:
       return Allow();
-    case __NR_access:
     case __NR_open:
     case __NR_openat:
       DCHECK(broker_process_);