Disable timestamps in WebGL.

third_party/WebKit/Source/modules/webgl/EXTDisjointTimerQuery.cpp

 // Copyright 2015 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 "modules/webgl/EXTDisjointTimerQuery.h"
 
 #include "bindings/modules/v8/WebGLAny.h"
 #include "modules/webgl/WebGLRenderingContextBase.h"
 #include "modules/webgl/WebGLTimerQueryEXT.h"
 
@@ skipping 122 matching lines @@
     if (target != GL_TIMESTAMP_EXT) {
         scoped.context()->webContext()->synthesizeGLError(GL_INVALID_ENUM);
         return;
     }
 
     if (query->hasTarget() && query->target() != target) {
         scoped.context()->webContext()->synthesizeGLError(GL_INVALID_OPERATION);
         return;
     }
 
-    scoped.context()->webContext()->queryCounterEXT(query->object(), target);
+    // Timestamps are disabled in WebGL due to lack of driver support, so we don't actually perform a GL call

[Ken Russell (switch to Gerrit), 2016/03/24 17:02:26]

Let's clarify "due to lack of driver support on multiple platforms".

     query->setTarget(target);
     query->resetCachedResult();
 }
 
 ScriptValue EXTDisjointTimerQuery::getQueryEXT(ScriptState* scriptState, GLenum target, GLenum pname)
 {
     WebGLExtensionScopedContext scoped(this);
     if (scoped.isLost())
         return ScriptValue::createNull(scriptState);
 
@@ skipping 51 matching lines @@
     WebGLExtension::trace(visitor);
 }
 
 EXTDisjointTimerQuery::EXTDisjointTimerQuery(WebGLRenderingContextBase* context)
     : WebGLExtension(context)
 {
     context->extensionsUtil()->ensureExtensionEnabled("GL_EXT_disjoint_timer_query");
 }
 
 } // namespace blink