Make it possible to have 1 PpapiGlobals per thread. Update unit tests.

ppapi/shared_impl/ppapi_globals.cc

Index: ppapi/shared_impl/ppapi_globals.cc
diff --git a/ppapi/shared_impl/ppapi_globals.cc b/ppapi/shared_impl/ppapi_globals.cc
index 9b5e9a82cb3fede21d10ab13b46f095acb127d8f..859b034be8cf2e8434de4ea464433ac6a09e56af 100644
--- a/ppapi/shared_impl/ppapi_globals.cc
+++ b/ppapi/shared_impl/ppapi_globals.cc
@@ -8,6 +8,12 @@
 
 namespace ppapi {
 
+namespace {
+
+base::ThreadLocalPointer<PpapiGlobals> tls_ppapi_globals_for_test;
+
+}  // namespace
+
 PpapiGlobals* PpapiGlobals::ppapi_globals_ = NULL;
 
 PpapiGlobals::PpapiGlobals() {
@@ -15,9 +21,26 @@ PpapiGlobals::PpapiGlobals() {
   ppapi_globals_ = this;
 }
 
+PpapiGlobals::PpapiGlobals(ForTest) {
+  DCHECK(!ppapi_globals_);
+}
+
 PpapiGlobals::~PpapiGlobals() {
-  DCHECK(ppapi_globals_ == this);
+  DCHECK(ppapi_globals_ == this || !ppapi_globals_);
   ppapi_globals_ = NULL;
 }
 
+// static
+void PpapiGlobals::SetPpapiGlobalsOnThreadForTest(PpapiGlobals* ptr) {
+  // If we're using a per-thread PpapiGlobals, we should not have a global one.
+  // If we allowed it, it would always over-ride the "test" versions.
+  DCHECK(!ppapi_globals_);
+  tls_ppapi_globals_for_test.Set(ptr);
+}
+
+// static
+PpapiGlobals* PpapiGlobals::GetThreadLocalPointer() {
+  return tls_ppapi_globals_for_test.Get();
+}
+
 }  // namespace ppapi