[PPAPI] Add browser tests for compositor API

ppapi/examples/compositor/compositor.cc

Index: ppapi/examples/compositor/compositor.cc
diff --git a/ppapi/examples/compositor/compositor.cc b/ppapi/examples/compositor/compositor.cc
index d437bc84b77aa894aafa3d744986be980d43a7fc..ccb93be2f73ec38c0ce46365d119014ea995fe01 100644
--- a/ppapi/examples/compositor/compositor.cc
+++ b/ppapi/examples/compositor/compositor.cc
@@ -72,6 +72,7 @@ class DemoInstance : public pp::Instance, public pp::Graphics3DClient {
   void InitGL(int32_t result);
   GLuint PrepareFramebuffer();
   pp::ImageData PrepareImage();
+  void PrepareLayers(int32_t frame);
   void Paint(int32_t result, int32_t frame);
   void OnTextureReleased(int32_t result, GLuint texture);
   void OnImageReleased(int32_t result, const pp::ImageData& image);
@@ -106,8 +107,7 @@ DemoInstance::DemoInstance(PP_Instance instance)
       context_(NULL),
       fbo_(0),
       rbo_(0),
-      compositor_(this),
-      rebuild_layers_(false),
+      rebuild_layers_(true),
       total_resource_(0),
       cube_(new SpinningCube()) {
   RequestInputEvents(PP_INPUTEVENT_CLASS_MOUSE);
@@ -147,11 +147,7 @@ bool DemoInstance::HandleInputEvent(const pp::InputEvent& event) {
 void DemoInstance::Graphics3DContextLost() {
   fbo_ = 0;
   rbo_ = 0;
-  compositor_.ResetLayers();
-  color_layer_ = pp::CompositorLayer();
-  stable_texture_layer_ = pp::CompositorLayer();
-  texture_layer_ = pp::CompositorLayer();
-  image_layer_ = pp::CompositorLayer();
+  rebuild_layers_ = true;
   total_resource_ -= static_cast<int32_t>(textures_.size());
   textures_.clear();
   delete context_;
@@ -260,14 +256,12 @@ pp::ImageData DemoInstance::PrepareImage() {
 
 void DemoInstance::Paint(int32_t result, int32_t frame) {
   assert(result == PP_OK);
-
   if (result != PP_OK || !context_)
     return;
 
-  int32_t rv;
-
   if (rebuild_layers_) {
-    compositor_.ResetLayers();
+    compositor_ = pp::Compositor(this);
+    assert(BindGraphics(compositor_));
     color_layer_ = pp::CompositorLayer();
     stable_texture_layer_ = pp::CompositorLayer();
     texture_layer_ = pp::CompositorLayer();
@@ -276,6 +270,21 @@ void DemoInstance::Paint(int32_t result, int32_t frame) {
     rebuild_layers_ = false;
   }
 
+  PrepareLayers(frame);
+
+  int32_t rv = compositor_.CommitLayers(
+      callback_factory_.NewCallback(&DemoInstance::Paint, ++frame));
+  assert(rv == PP_OK_COMPLETIONPENDING);
+
+  pp::VarDictionary dict;
+  dict.Set("total_resource", total_resource_);
+  size_t free_resource = textures_.size() + images_.size();
+  dict.Set("free_resource", static_cast<int32_t>(free_resource));
+  PostMessage(dict);
+}
+
+void DemoInstance::PrepareLayers(int32_t frame) {
+  int32_t rv;
   float factor_sin = sin(M_PI / 180 * frame);
   float factor_cos = cos(M_PI / 180 * frame);
   {
@@ -395,16 +404,6 @@ void DemoInstance::Paint(int32_t result, int32_t frame) {
     rv = texture_layer_.SetPremultipliedAlpha(PP_FALSE);
     assert(rv == PP_OK);
   }
-
-  rv = compositor_.CommitLayers(
-      callback_factory_.NewCallback(&DemoInstance::Paint, ++frame));
-  assert(rv == PP_OK_COMPLETIONPENDING);
-
-  pp::VarDictionary dict;
-  dict.Set(pp::Var("total_resource"), pp::Var(total_resource_));
-  dict.Set(pp::Var("free_resource"),
-      pp::Var((int32_t)(textures_.size() + images_.size())));
-  PostMessage(dict);
 }
 
 void DemoInstance::OnTextureReleased(int32_t result, GLuint texture) {