Revert of Revert of Implement software fallback for PPB_VideoDecoder.

ppapi/proxy/video_decoder_resource.cc

Index: ppapi/proxy/video_decoder_resource.cc
diff --git a/ppapi/proxy/video_decoder_resource.cc b/ppapi/proxy/video_decoder_resource.cc
index 95365e8bba8e67e29c9834a7d0c118ef122067ae..2ca5ce2de8e015d5625f9dfa280424c446884f84 100644
--- a/ppapi/proxy/video_decoder_resource.cc
+++ b/ppapi/proxy/video_decoder_resource.cc
@@ -7,6 +7,7 @@
 #include "base/bind.h"
 #include "gpu/command_buffer/client/gles2_cmd_helper.h"
 #include "gpu/command_buffer/client/gles2_implementation.h"
+#include "gpu/command_buffer/common/mailbox.h"
 #include "ipc/ipc_message.h"
 #include "ppapi/c/pp_errors.h"
 #include "ppapi/c/ppb_opengles2.h"
@@ -112,7 +113,7 @@
                          enter_create.functions()->CreateGraphics3D(
                              pp_instance(), graphics_context, attrib_list));
     EnterResourceNoLock<PPB_Graphics3D_API> enter_graphics(graphics3d_.get(),
-                                                           true);
+                                                           false);
     if (enter_graphics.failed())
       return PP_ERROR_BADRESOURCE;
 
@@ -332,8 +333,10 @@
     const ResourceMessageReplyParams& params,
     uint32_t num_textures,
     const PP_Size& size,
-    uint32_t texture_target) {
+    uint32_t texture_target,
+    const std::vector<gpu::Mailbox>& mailboxes) {
   DCHECK(num_textures);
+  DCHECK(mailboxes.empty() || mailboxes.size() == num_textures);
   std::vector<uint32_t> texture_ids(num_textures);
   if (gles2_impl_) {
     gles2_impl_->GenTextures(num_textures, &texture_ids.front());
@@ -360,6 +363,10 @@
                                 GL_UNSIGNED_BYTE,
                                 NULL);
       }
+      if (!mailboxes.empty()) {
+        gles2_impl_->ProduceTextureCHROMIUM(
+            GL_TEXTURE_2D, reinterpret_cast<const GLbyte*>(mailboxes[i].name));
+      }
 
       textures_.insert(
           std::make_pair(texture_ids[i], Texture(texture_target, size)));