gpu: Avoid integer overflow when setting up client side buffers

gpu/command_buffer/client/vertex_array_object_manager.cc

 // Copyright (c) 2012 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 "gpu/command_buffer/client/vertex_array_object_manager.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include "base/logging.h"
@@ skipping 468 matching lines @@
   for (; dst < end; src += real_stride, dst += bytes_per_element) {
     memcpy(dst, src, bytes_per_element);
   }
   return bytes_needed;
 }
 
 bool VertexArrayObjectManager::IsDefaultVAOBound() const {
   return bound_vertex_array_object_ == default_vertex_array_object_;
 }
 
+bool VertexArrayObjectManager::SupportsClientSideBuffers() {
+  return support_client_side_arrays_ &&
+         bound_vertex_array_object_->HaveEnabledClientSideBuffers();
+}
+
 // Returns true if buffers were setup.
 bool VertexArrayObjectManager::SetupSimulatedClientSideBuffers(
     const char* function_name,
     GLES2Implementation* gl,
     GLES2CmdHelper* gl_helper,
     GLsizei num_elements,
     GLsizei primcount,
     bool* simulated) {
   *simulated = false;
-  if (!support_client_side_arrays_)
-    return true;
-  if (!bound_vertex_array_object_->HaveEnabledClientSideBuffers()) {
-    return true;
-  }
+  if (!SupportsClientSideBuffers())
+    return false;
+
   if (!IsDefaultVAOBound()) {
     gl->SetGLError(
         GL_INVALID_OPERATION, function_name,
         "client side arrays not allowed with vertex array object");
     return false;
   }
   *simulated = true;
   GLsizei total_size = 0;
   // Compute the size of the buffer we need.
   const VertexArrayObject::VertexAttribs& vertex_attribs =
@@ skipping 127 matching lines @@
       function_name, gl, gl_helper, num_elements, primcount,
       &simulated_client_side_buffers);
   *simulated = *simulated || simulated_client_side_buffers;
   return true;
 }
 
 }  // namespace gles2
 }  // namespace gpu