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

ppapi/shared_impl/ppapi_globals.h

Index: ppapi/shared_impl/ppapi_globals.h
diff --git a/ppapi/shared_impl/ppapi_globals.h b/ppapi/shared_impl/ppapi_globals.h
index b3d7d555514785a41f57891eb5ec872c04427c78..ddefb5a43f7da4b9bb93a59c4fabdfb86611da1e 100644
--- a/ppapi/shared_impl/ppapi_globals.h
+++ b/ppapi/shared_impl/ppapi_globals.h
@@ -6,11 +6,16 @@
 #define PPAPI_SHARED_IMPL_PPAPI_GLOBALS_H_
 
 #include "base/basictypes.h"
+#include "base/threading/thread_local.h"  // For testing purposes only.
 #include "ppapi/c/pp_instance.h"
 #include "ppapi/c/pp_module.h"
 #include "ppapi/shared_impl/api_id.h"
 #include "ppapi/shared_impl/ppapi_shared_export.h"
 
+namespace base {
+class Lock;
+}
+
 namespace ppapi {
 
 class CallbackTracker;
@@ -22,16 +27,40 @@ class VarTracker;
 class PPAPI_SHARED_EXPORT PpapiGlobals {
  public:
   PpapiGlobals();
+
+  // This constructor is to be used only for making a PpapiGlobal for testing
+  // purposes. This avoids setting the global static ppapi_globals_. For unit
+  // tests that use this feature, the "test" PpapiGlobals should be constructed
+  // using this method. See SetPpapiGlobalsOnThreadForTest for more information.
+  struct ForTest {};
+  PpapiGlobals(ForTest);
+
   virtual ~PpapiGlobals();
 
   // Getter for the global singleton.
-  inline static PpapiGlobals* Get() { return ppapi_globals_; }
+  inline static PpapiGlobals* Get() {
+    if (ppapi_globals_)
+      return ppapi_globals_;
+    return ppapi_globals_for_test_.Get();
+  }
+
+  // This allows us to set a given PpapiGlobals object as the PpapiGlobals for
+  // a given thread. After setting the PpapiGlobals for a thread, Get() will
+  // return that PpapiGlobals when Get() is called on that thread. Other threads
+  // are unaffected. This allows us to have tests which use >1 PpapiGlobals in
+  // the same process, e.g. for having 1 thread emulate the "host" and 1 thread
+  // emulate the "plugin".
+  //
+  // PpapiGlobals object must have been constructed using the "ForTest"
+  // parameter.
+  static void SetPpapiGlobalsOnThreadForTest(PpapiGlobals* ptr);
 
   // Retrieves the corresponding tracker.
   virtual ResourceTracker* GetResourceTracker() = 0;
   virtual VarTracker* GetVarTracker() = 0;
   virtual CallbackTracker* GetCallbackTrackerForInstance(
       PP_Instance instance) = 0;
+  virtual base::Lock* GetProxyLock() = 0;
 
   // Returns the function object corresponding to the given ID, or NULL if
   // there isn't one.
@@ -44,6 +73,11 @@ class PPAPI_SHARED_EXPORT PpapiGlobals {
  private:
   static PpapiGlobals* ppapi_globals_;
 
+  // The thread-local pointer is used only for unit testing. It should always be
+  // NULL when running in production, to allow separate threads to have distinct
+  // "globals".
+  static base::ThreadLocalPointer<PpapiGlobals> ppapi_globals_for_test_;
+
   DISALLOW_COPY_AND_ASSIGN(PpapiGlobals);
 };