implement getBufferSubDataAsync prototype

gpu/command_buffer/client/gles2_implementation.cc

Index: gpu/command_buffer/client/gles2_implementation.cc
diff --git a/gpu/command_buffer/client/gles2_implementation.cc b/gpu/command_buffer/client/gles2_implementation.cc
index cbbe0f49544afd6eacf12b52d410382726757db9..836cbde0d304806c6a164f48ea890275f5e19ef6 100644
--- a/gpu/command_buffer/client/gles2_implementation.cc
+++ b/gpu/command_buffer/client/gles2_implementation.cc
@@ -373,6 +373,10 @@ void GLES2Implementation::FreeEverything() {
   helper_->FreeRingBuffer();
 }
 
+void GLES2Implementation::FreeSharedMemory(void* mem) {
+  mapped_memory_->FreePendingToken(mem, helper_->InsertToken());
+}
+
 void GLES2Implementation::RunIfContextNotLost(const base::Closure& callback) {
   if (!lost_context_callback_run_)
     callback.Run();
@@ -1640,6 +1644,54 @@ GLint GLES2Implementation::GetAttribLocation(
   return loc;
 }
 
+void* GLES2Implementation::GetBufferSubDataAsyncCHROMIUM(
+    GLenum target, GLintptr offset, GLsizeiptr size) {
+  const char* name = "glGetBufferSubDataAsyncCHROMIUM";
+  GPU_CLIENT_SINGLE_THREAD_CHECK();
+  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] " << name << "("
+      << GLES2Util::GetStringEnum(target) << ", " << offset << ", "
+      << size << ")");
+  switch (target) {
+    case GL_ARRAY_BUFFER:
+    case GL_ELEMENT_ARRAY_BUFFER:
+    case GL_COPY_READ_BUFFER:
+    case GL_COPY_WRITE_BUFFER:
+    case GL_PIXEL_PACK_BUFFER:
+    case GL_PIXEL_UNPACK_BUFFER:
+    case GL_TRANSFORM_FEEDBACK_BUFFER:
+    case GL_UNIFORM_BUFFER:
+      break;
+    default:
+      SetGLError(GL_INVALID_ENUM, name, "invalid target");
+      return nullptr;
+  }
+
+  GLuint buffer = GetBoundBufferHelper(target);
+  if (buffer == 0) {
+    SetGLError(GL_INVALID_OPERATION, name, "no buffer bound");
+    return nullptr;
+  }
+
+  if (!ValidateSize("glMapBufferRange", size) ||
+      !ValidateOffset("glMapBufferRange", offset)) {
+    SetGLError(GL_INVALID_VALUE, name, "invalid size/offset");
+    return nullptr;
+  }
+
+  int32_t shm_id;
+  unsigned int shm_offset;
+  void* shm_ptr = mapped_memory_->Alloc(size, &shm_id, &shm_offset);
+  if (!shm_ptr) {
+    SetGLError(GL_OUT_OF_MEMORY, name, "out of memory");
+    return nullptr;
+  }
+
+  helper_->GetBufferSubDataAsyncCHROMIUM(target, offset, size,
+      shm_id, shm_offset);
+
+  return shm_ptr;
+}
+
 GLint GLES2Implementation::GetUniformLocationHelper(
     GLuint program, const char* name) {
   typedef cmds::GetUniformLocation::Result Result;