Convert resources to take an instance key instead of an Instance*.

ppapi/cpp/private/flash_clipboard.cc

Index: ppapi/cpp/private/flash_clipboard.cc
diff --git a/ppapi/cpp/private/flash_clipboard.cc b/ppapi/cpp/private/flash_clipboard.cc
index 8634eafc8adde463a9fa2be7609ab2a8dfca857d..ff9aeadce404c2c999ad89d92ffc819426745159 100644
--- a/ppapi/cpp/private/flash_clipboard.cc
+++ b/ppapi/cpp/private/flash_clipboard.cc
@@ -6,7 +6,7 @@
 
 #include "ppapi/c/pp_bool.h"
 #include "ppapi/c/pp_errors.h"
-#include "ppapi/cpp/instance.h"
+#include "ppapi/cpp/instance_handle.h"
 #include "ppapi/cpp/module_impl.h"
 #include "ppapi/cpp/var.h"
 
@@ -28,26 +28,26 @@ bool Clipboard::IsAvailable() {
 }
 
 // static
-bool Clipboard::IsFormatAvailable(Instance* instance,
+bool Clipboard::IsFormatAvailable(const InstanceHandle& instance,
                                   PP_Flash_Clipboard_Type clipboard_type,
                                   PP_Flash_Clipboard_Format format) {
   bool rv = false;
   if (has_interface<PPB_Flash_Clipboard>()) {
     rv = PP_ToBool(get_interface<PPB_Flash_Clipboard>()->IsFormatAvailable(
-        instance->pp_instance(), clipboard_type, format));
+        instance.pp_instance(), clipboard_type, format));
   }
   return rv;
 }
 
 // static
-bool Clipboard::ReadPlainText(Instance* instance,
+bool Clipboard::ReadPlainText(const InstanceHandle& instance,
                               PP_Flash_Clipboard_Type clipboard_type,
                               std::string* text_out) {
   bool rv = false;
   if (has_interface<PPB_Flash_Clipboard>()) {
-    Var v(Var::PassRef(),
+    Var v(PASS_REF,
           get_interface<PPB_Flash_Clipboard>()->ReadPlainText(
-              instance->pp_instance(),
+              instance.pp_instance(),
               clipboard_type));
     if (v.is_string()) {
       rv = true;
@@ -58,13 +58,13 @@ bool Clipboard::ReadPlainText(Instance* instance,
 }
 
 // static
-bool Clipboard::WritePlainText(Instance* instance,
+bool Clipboard::WritePlainText(const InstanceHandle& instance,
                                PP_Flash_Clipboard_Type clipboard_type,
                                const std::string& text) {
   bool rv = false;
   if (has_interface<PPB_Flash_Clipboard>()) {
     rv = (get_interface<PPB_Flash_Clipboard>()->WritePlainText(
-              instance->pp_instance(),
+              instance.pp_instance(),
               clipboard_type,
               Var(text).pp_var()) == PP_OK);
   }