Added support for EXTDisjointTimerQuery on the Blink side.

Source/modules/webgl/EXTDisjointTimerQuery.idl

+// 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.
+
+typedef unsigned long long GLuint64EXT;
+
+[
+    DoNotCheckConstants,
+    NoInterfaceObject,
+    TypeChecking=Interface,
+    GarbageCollected,
+    SetWrapperReferenceFrom=canvas,
+] interface EXTDisjointTimerQuery {
+    const GLenum QUERY_COUNTER_BITS_EXT      = 0x8864;
+    const GLenum CURRENT_QUERY_EXT           = 0x8865;
+    const GLenum QUERY_RESULT_EXT            = 0x8866;
+    const GLenum QUERY_RESULT_AVAILABLE_EXT  = 0x8867;
+    const GLenum TIME_ELAPSED_EXT            = 0x88BF;
+    const GLenum TIMESTAMP_EXT               = 0x8E28;
+    const GLenum GPU_DISJOINT_EXT            = 0x8FBB;
+
+    WebGLTimerQueryEXT createQueryEXT();
+    void deleteQueryEXT([Default=Undefined] WebGLTimerQueryEXT? query);
+    boolean isQueryEXT([Default=Undefined] WebGLTimerQueryEXT? query);
+    void beginQueryEXT(GLenum target, [Default=Undefined] WebGLTimerQueryEXT? query);
+    void endQueryEXT(GLenum target);
+    void queryCounterEXT([Default=Undefined] WebGLTimerQueryEXT? query, GLenum target);
+    [CallWith=ScriptState] any getQueryEXT(GLenum target, GLenum pname);
+    [CallWith=ScriptState] any getQueryObjectEXT([Default=Undefined] WebGLTimerQueryEXT? query, GLenum pname);
+};