PPAPI: Make GLES2 calls resilient to bad/dead resources.

ppapi/proxy/ppapi_command_buffer_proxy.cc

Index: ppapi/proxy/ppapi_command_buffer_proxy.cc
diff --git a/ppapi/proxy/ppapi_command_buffer_proxy.cc b/ppapi/proxy/ppapi_command_buffer_proxy.cc
index d748678ca1d740283b5d9f2e270f2b7ab2d9819b..5861071c0aafb6690860568412b17e87dc552366 100644
--- a/ppapi/proxy/ppapi_command_buffer_proxy.cc
+++ b/ppapi/proxy/ppapi_command_buffer_proxy.cc
@@ -8,6 +8,7 @@
 #include "ppapi/proxy/proxy_channel.h"
 #include "ppapi/shared_impl/api_id.h"
 #include "ppapi/shared_impl/host_resource.h"
+#include "ppapi/shared_impl/proxy_lock.h"
 
 namespace ppapi {
 namespace proxy {
@@ -48,14 +49,12 @@ gpu::CommandBuffer::State PpapiCommandBufferProxy::GetState() {
 }
 
 gpu::CommandBuffer::State PpapiCommandBufferProxy::GetLastState() {
-  // Note: The locking command buffer wrapper does not take a global lock before
-  // calling this function.
+  ppapi::ProxyLock::AssertAcquiredDebugOnly();
   return last_state_;
 }
 
 int32 PpapiCommandBufferProxy::GetLastToken() {
-  // Note: The locking command buffer wrapper does not take a global lock before
-  // calling this function.
+  ppapi::ProxyLock::AssertAcquiredDebugOnly();
   return last_state_.token;
 }