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 8ca17e442d1e20b7b6f2d70b25c3e6caaa8269d8..c7f5526ff8933814e490bd00f3639b2f7e4251b8 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 {
@@ -74,14 +75,12 @@ 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();

[dmichael (off chromium), 2013/09/26 22:26:38]

I was able to confirm with From Dust that these are both called, though I don't
know where for the case of GetLastState. CHECK(false) caused a crash.

However, with the AssertAcquiredDebugOnly, no crash. So it appears we *do* have
the lock here now, at no extra charge.

   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;
 }