Replace the RenderProcessHost.PID function that returns the OS-generated

process ID with an internally-generated id() function. This allows us the
guarantee that the IDs are unique over the entire run of the application.

This also cleans up some code associated with managing the PID.

The main potentially interesting change is now the PID is set uniquely for
every creation of RenderProcessHost. It used to be set cleared if the process
went away, and re-set if the process was re-created. The ID generation is in
ChildProcesInfo so it is also unique between workers and plugins. I had to
change some significant things in resource_dispatcher_host_unittest to take
into account this new generation of IDs.

BUG=17828
TEST=none
Review URL: http://codereview.chromium.org/160203

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@24899 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 34 insertions, 11 deletions

diff --git a/chrome/common/child_process_info.cc b/chrome/common/child_process_info.cc
index 819b7fc..770c9866 100644
--- a/chrome/common/child_process_info.cc
+++ b/chrome/common/child_process_info.cc
@@ -7,12 +7,34 @@
 #include <limits>
 
 #include "app/l10n_util.h"
+#include "base/atomicops.h"
 #include "base/logging.h"
 #include "base/process_util.h"
 #include "base/rand_util.h"
 #include "base/string_util.h"
 #include "grit/generated_resources.h"
 
+ChildProcessInfo::ChildProcessInfo(const ChildProcessInfo& original)
+    : type_(original.type_),
+      name_(original.name_),
+      id_(original.id_),
+      process_(original.process_) {
+}
+
+ChildProcessInfo::~ChildProcessInfo() {
+}
+
+ChildProcessInfo& ChildProcessInfo::operator=(
+    const ChildProcessInfo& original) {
+  if (&original != this) {
+    type_ = original.type_;
+    name_ = original.name_;
+    id_ = original.id_;
+    process_ = original.process_;
+  }
+  return *this;
+}
+
 std::wstring ChildProcessInfo::GetTypeNameInEnglish(
     ChildProcessInfo::ProcessType type) {
   switch (type) {
@@ -56,17 +78,11 @@ std::wstring ChildProcessInfo::GetLocalizedTitle() const {
   return l10n_util::GetStringF(message_id, title);
 }
 
-ChildProcessInfo::ChildProcessInfo(ProcessType type) {
-  // This constructor is only used by objects which derive from this class,
-  // which means *this* is a real object that refers to a child process, and not
-  // just a simple object that contains information about it.  So add it to our
-  // list of running processes.
-  type_ = type;
-  pid_ = -1;
-}
-
-
-ChildProcessInfo::~ChildProcessInfo() {
+ChildProcessInfo::ChildProcessInfo(ProcessType type, int id) : type_(type) {
+  if (id == -1)
+    id_ = GenerateChildProcessUniqueId();
+  else
+    id_ = id;
 }
 
 std::string ChildProcessInfo::GenerateRandomChannelID(void* instance) {
@@ -80,3 +96,10 @@ std::string ChildProcessInfo::GenerateRandomChannelID(void* instance) {
                       base::GetCurrentProcId(), instance,
                       base::RandInt(0, std::numeric_limits<int>::max()));
 }
+
+// static
+int ChildProcessInfo::GenerateChildProcessUniqueId() {
+  // This function must be threadsafe.
+  static base::subtle::Atomic32 last_unique_child_id = 0;
+  return base::subtle::NoBarrier_AtomicIncrement(&last_unique_child_id, 1);
+}