[PPAPI] Add browser tests for compositor API

ppapi/proxy/compositor_resource.cc

Index: ppapi/proxy/compositor_resource.cc
diff --git a/ppapi/proxy/compositor_resource.cc b/ppapi/proxy/compositor_resource.cc
index 3ada734849839aca56078ac7e3859b6d574df1a6..9688f6054bc5d9796fbbfd86eacd16e61445b337 100644
--- a/ppapi/proxy/compositor_resource.cc
+++ b/ppapi/proxy/compositor_resource.cc
@@ -6,6 +6,7 @@
 
 #include "base/logging.h"
 #include "ppapi/proxy/ppapi_messages.h"
+#include "ppapi/thunk/enter.h"
 
 namespace ppapi {
 namespace proxy {
@@ -14,6 +15,7 @@ CompositorResource::CompositorResource(Connection connection,
                                        PP_Instance instance)
     : PluginResource(connection, instance),
       layer_reset_(true),
+      bound_to_instance_(false),
       last_resource_id_(0) {
   SendCreate(RENDERER, PpapiHostMsg_Compositor_Create());
 }
@@ -39,6 +41,9 @@ void CompositorResource::OnReplyReceived(
 }
 
 PP_Resource CompositorResource::AddLayer() {
+  if (!bound_to_instance_)
+    return 0;
+
   scoped_refptr<CompositorLayerResource> resource(new CompositorLayerResource(
       connection(), pp_instance(), this));
   layers_.push_back(resource);
@@ -47,6 +52,9 @@ PP_Resource CompositorResource::AddLayer() {
 
 int32_t CompositorResource::CommitLayers(
     const scoped_refptr<ppapi::TrackedCallback>& callback) {
+  if (!bound_to_instance_)
+    return PP_ERROR_FAILED;
+
   if (IsInProgress())
     return PP_ERROR_INPROGRESS;
 
@@ -72,12 +80,41 @@ int32_t CompositorResource::CommitLayers(
 }
 
 int32_t CompositorResource::ResetLayers() {
+  if (!bound_to_instance_)
+    return PP_ERROR_FAILED;
+
   if (IsInProgress())
     return PP_ERROR_INPROGRESS;
+
   ResetLayersInternal();
   return PP_OK;
 }
 
+void CompositorResource::BindToInstance(bool bound) {
+  ProxyLock::AssertAcquiredDebugOnly();
+
+  if (bound == bound_to_instance_)
+    return;
+  bound_to_instance_ = bound;
+
+  // Reset layers when the compositor is un bound from the instance.
+  if (!bound_to_instance_)
+    ResetLayersInternal();
+}
+
+void CompositorResource::NotifyLastPluginRefWasDeleted() {
+  ProxyLock::AssertAcquiredDebugOnly();
+
+  PluginResource::NotifyLastPluginRefWasDeleted();
+  if (bound_to_instance_) {
+    ppapi::thunk::EnterInstanceNoLock enter(pp_instance());
+    CHECK(enter.succeeded());
+    enter.functions()->BindGraphics(pp_instance(), 0);
+    // BindToInstance(0) should be called by PPB_Instance_Proxy::BindGraphics().
+    CHECK(!bound_to_instance_);
+   }
+}
+
 void CompositorResource::OnPluginMsgCommitLayersReply(
     const ResourceMessageReplyParams& params) {
   if (!TrackedCallback::IsPending(commit_callback_))