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

ppapi/proxy/plugin_globals.h

Index: ppapi/proxy/plugin_globals.h
diff --git a/ppapi/proxy/plugin_globals.h b/ppapi/proxy/plugin_globals.h
index ffcf01e016e51cd08721fc7db76b026dbb54b142..e6b35c09986eb36e4355fac92744bb5608855dca 100644
--- a/ppapi/proxy/plugin_globals.h
+++ b/ppapi/proxy/plugin_globals.h
@@ -6,6 +6,7 @@
 #define PPAPI_PROXY_PLUGIN_GLOBALS_H_
 
 #include "base/compiler_specific.h"
+#include "base/synchronization/lock.h"
 #include "ppapi/proxy/plugin_resource_tracker.h"
 #include "ppapi/proxy/plugin_var_tracker.h"
 #include "ppapi/proxy/ppapi_proxy_export.h"
@@ -20,12 +21,17 @@ class PluginProxyDelegate;
 class PPAPI_PROXY_EXPORT PluginGlobals : public PpapiGlobals {
  public:
   PluginGlobals();
+  PluginGlobals(PpapiGlobals::ForTest);
   virtual ~PluginGlobals();
 
   // Getter for the global singleton. Generally, you should use
   // PpapiGlobals::Get() when possible. Use this only when you need some
   // plugin-specific functionality.
-  inline static PluginGlobals* Get() { return plugin_globals_; }
+  inline static PluginGlobals* Get() {
+    if (plugin_globals_)
+      return plugin_globals_;
+    return static_cast<PluginGlobals*>(PpapiGlobals::Get());
+  }
 
   // PpapiGlobals implementation.
   virtual ResourceTracker* GetResourceTracker() OVERRIDE;
@@ -35,6 +41,7 @@ class PPAPI_PROXY_EXPORT PluginGlobals : public PpapiGlobals {
   virtual FunctionGroupBase* GetFunctionAPI(PP_Instance inst,
                                             ApiID id) OVERRIDE;
   virtual PP_Module GetModuleForInstance(PP_Instance instance) OVERRIDE;
+  virtual base::Lock* GetProxyLock() OVERRIDE;
 
   // Getters for the plugin-specific versions.
   PluginResourceTracker* plugin_resource_tracker() {
@@ -59,6 +66,7 @@ class PPAPI_PROXY_EXPORT PluginGlobals : public PpapiGlobals {
   PluginResourceTracker plugin_resource_tracker_;
   PluginVarTracker plugin_var_tracker_;
   scoped_refptr<CallbackTracker> callback_tracker_;
+  base::Lock proxy_lock_;
 
   DISALLOW_COPY_AND_ASSIGN(PluginGlobals);
 };