Disable timestamps in WebGL.

gpu/command_buffer/client/gles2_implementation.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.
 
 // A class to emulate GLES2 over command buffers.
 
 #include "gpu/command_buffer/client/gles2_implementation.h"
 
 #include <GLES2/gl2.h>
 #include <GLES2/gl2ext.h>
@@ skipping 5465 matching lines @@
 }
 
 void GLES2Implementation::GetQueryivEXT(
     GLenum target, GLenum pname, GLint* params) {
   GPU_CLIENT_SINGLE_THREAD_CHECK();
   GPU_CLIENT_LOG("[" << GetLogPrefix() << "] GetQueryivEXT("
                  << GLES2Util::GetStringQueryTarget(target) << ", "
                  << GLES2Util::GetStringQueryParameter(pname) << ", "
                  << static_cast<const void*>(params) << ")");
   if (pname == GL_QUERY_COUNTER_BITS_EXT) {
-    // We convert all queries to CPU time so we support 64 bits.
-    *params = 64;
+    switch (target) {
+      case GL_TIMESTAMP_EXT:
+        // Overall reliable driver support for timestamps is limited, so we
+        // disable the timestamp portion of this extension to encourage use of
+        // the better supported time elapsed queries.
+        *params = 0;
+        break;
+      case GL_TIME_ELAPSED_EXT:
+        // We convert all queries to CPU time so we support 64 bits.
+        *params = 64;
+        break;
+      default:
+        SetGLErrorInvalidEnum("glGetQueryivEXT", target, "target");
+        break;
+    }
     return;
   } else if (pname != GL_CURRENT_QUERY_EXT) {
     SetGLErrorInvalidEnum("glGetQueryivEXT", pname, "pname");
     return;
   }
   QueryTracker::Query* query = query_tracker_->GetCurrentQuery(target);
   *params = query ? query->id() : 0;
   GPU_CLIENT_LOG("  " << *params);
   CheckGLError();
 }
@@ skipping 1325 matching lines @@
   cached_extensions_.clear();
 }
 
 // Include the auto-generated part of this file. We split this because it means
 // we can easily edit the non-auto generated parts right here in this file
 // instead of having to edit some template or the code generator.
 #include "gpu/command_buffer/client/gles2_implementation_impl_autogen.h"
 
 }  // namespace gles2
 }  // namespace gpu