Define magic descriptors in one place.

content/zygote/zygote_linux.cc

Index: content/zygote/zygote_linux.cc
diff --git a/content/zygote/zygote_linux.cc b/content/zygote/zygote_linux.cc
index 4b83444929b4807b2414a4d0b0ba9e4b572ae923..f1a0452e3e7f2f30779394269f29ef2964ecdccc 100644
--- a/content/zygote/zygote_linux.cc
+++ b/content/zygote/zygote_linux.cc
@@ -42,8 +42,6 @@ void SIGCHLDHandler(int signal) {
 
 }  // namespace
 
-const int Zygote::kMagicSandboxIPCDescriptor;
-
 Zygote::Zygote(int sandbox_flags,
                ZygoteForkDelegate* helper)
     : sandbox_flags_(sandbox_flags),
@@ -77,7 +75,7 @@ bool Zygote::ProcessRequests() {
     // Let the ZygoteHost know we are ready to go.
     // The receiving code is in content/browser/zygote_host_linux.cc.
     std::vector<int> empty;
-    bool r = UnixDomainSocket::SendMsg(kBrowserDescriptor,
+    bool r = UnixDomainSocket::SendMsg(kMagicZygoteDescriptor,
                                        kZygoteHelloMessage,
                                        sizeof(kZygoteHelloMessage), empty);
 #if defined(OS_CHROMEOS)
@@ -94,7 +92,7 @@ bool Zygote::ProcessRequests() {
 
   for (;;) {
     // This function call can return multiple times, once per fork().
-    if (HandleRequestFromBrowser(kBrowserDescriptor))
+    if (HandleRequestFromBrowser(kMagicZygoteDescriptor))
       return true;
   }
 }
@@ -475,7 +473,7 @@ base::ProcessId Zygote::ReadArgsAndFork(const Pickle& pickle,
   if (!child_pid) {
     // This is the child process.
 
-    close(kBrowserDescriptor);  // Our socket from the browser.
+    close(kMagicZygoteDescriptor);  // Our socket from the browser.
     if (UsingSUIDSandbox())
       close(kZygoteIdFd);  // Another socket from the browser.
     base::GlobalDescriptors::GetInstance()->Reset(mapping);