Fix PPB_MouseLock.LockMouse crash and add tests.

ppapi/thunk/enter.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ppapi/thunk/enter.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/message_loop.h"
 #include "base/stringprintf.h"
@@ skipping 219 matching lines @@
 
 EnterInstance::~EnterInstance() {
 }
 
 EnterInstanceNoLock::EnterInstanceNoLock(PP_Instance instance)
     : EnterBase(),
       functions_(PpapiGlobals::Get()->GetInstanceAPI(instance)) {
   SetStateForFunctionError(instance, functions_, true);
 }
 
+EnterInstanceNoLock::EnterInstanceNoLock(
+    PP_Instance instance,
+    const PP_CompletionCallback& callback)
+    : EnterBase(0 /* resource */, callback),
+    // TODO(dmichael): This means that the callback_ we get is not associated
+    //                 even with the instance, but we should handle that for
+    //                 MouseLock (maybe others?).
+      functions_(PpapiGlobals::Get()->GetInstanceAPI(instance)) {
+  SetStateForFunctionError(instance, functions_, true);
+}
+
 EnterInstanceNoLock::~EnterInstanceNoLock() {
 }
 
 EnterResourceCreation::EnterResourceCreation(PP_Instance instance)
     : EnterBase(),
       functions_(PpapiGlobals::Get()->GetResourceCreationAPI(instance)) {
   SetStateForFunctionError(instance, functions_, true);
 }
 
 EnterResourceCreation::~EnterResourceCreation() {
 }
 
 EnterResourceCreationNoLock::EnterResourceCreationNoLock(PP_Instance instance)
     : EnterBase(),
       functions_(PpapiGlobals::Get()->GetResourceCreationAPI(instance)) {
   SetStateForFunctionError(instance, functions_, true);
 }
 
 EnterResourceCreationNoLock::~EnterResourceCreationNoLock() {
 }
 
 }  // namespace thunk
 }  // namespace ppapi