Fix partial swap support

webkit/common/gpu/context_provider_in_process.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "webkit/common/gpu/context_provider_in_process.h"
 
+#include <set>
+
 #include "base/bind.h"
 #include "base/callback_helpers.h"
+#include "base/strings/string_split.h"
 #include "base/strings/stringprintf.h"
 #include "cc/output/managed_memory_policy.h"
 #include "webkit/common/gpu/grcontext_for_webgraphicscontext3d.h"
 #include "webkit/common/gpu/managed_memory_policy_convert.h"
 
 namespace webkit {
 namespace gpu {
 
 class ContextProviderInProcess::LostContextCallbackProxy
     : public WebKit::WebGraphicsContext3D::WebGraphicsContextLostCallback {
@@ skipping 128 matching lines @@
   // provides the following capabilities:
   Capabilities caps;
   caps.bind_uniform_location = true;
   caps.discard_backbuffer = true;
   caps.map_image = true;
   caps.map_sub = true;
   caps.set_visibility = true;
   caps.shallow_flush = true;
   caps.texture_format_bgra8888 = true;
   caps.texture_rectangle = true;
+
+  WebKit::WebString extensions =
+      context3d_->getString(0x1F03 /* GL_EXTENSIONS */);
+  std::vector<std::string> extension_list;
+  base::SplitString(extensions.utf8(), ' ', &extension_list);
+  std::set<std::string> extension_set(extension_list.begin(),
+                                      extension_list.end());
+
+  caps.post_sub_buffer = extension_set.count("GL_CHROMIUM_post_sub_buffer") > 0;
   return caps;
 }
 
 WebKit::WebGraphicsContext3D* ContextProviderInProcess::Context3d() {
   DCHECK(context3d_);
   DCHECK(lost_context_callback_proxy_);  // Is bound to thread.
   DCHECK(context_thread_checker_.CalledOnValidThread());
 
   return context3d_.get();
 }
@@ skipping 85 matching lines @@
 void ContextProviderInProcess::SetMemoryPolicyChangedCallback(
     const MemoryPolicyChangedCallback& memory_policy_changed_callback) {
   DCHECK(context_thread_checker_.CalledOnValidThread());
   DCHECK(memory_policy_changed_callback_.is_null() ||
          memory_policy_changed_callback.is_null());
   memory_policy_changed_callback_ = memory_policy_changed_callback;
 }
 
 }  // namespace gpu
 }  // namespace webkit