Fix blink side WebGL2 sync object related behaviors.

third_party/WebKit/Source/modules/webgl/WebGL2RenderingContextBase.idl

Index: third_party/WebKit/Source/modules/webgl/WebGL2RenderingContextBase.idl
diff --git a/third_party/WebKit/Source/modules/webgl/WebGL2RenderingContextBase.idl b/third_party/WebKit/Source/modules/webgl/WebGL2RenderingContextBase.idl
index fdb841cdcaf86252422aef558930afcbb065783d..46371e0b2695a430dbee58876d0a5222b9b03b7f 100644
--- a/third_party/WebKit/Source/modules/webgl/WebGL2RenderingContextBase.idl
+++ b/third_party/WebKit/Source/modules/webgl/WebGL2RenderingContextBase.idl
@@ -2,7 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-typedef long long      GLint64;
+typedef long long GLint64;
+typedef unsigned long long GLuint64;
 
 [
     RuntimeEnabled=UnsafeES3APIs,
@@ -414,7 +415,7 @@ typedef long long      GLint64;
     WebGLSync fenceSync(GLenum condition, GLbitfield flags);
     GLboolean isSync(WebGLSync? sync);
     void deleteSync(WebGLSync? sync);
-    GLenum clientWaitSync(WebGLSync? sync, GLbitfield flags, GLint64 timeout);
+    GLenum clientWaitSync(WebGLSync? sync, GLbitfield flags, GLuint64 timeout);
     void waitSync(WebGLSync? sync, GLbitfield flags, GLint64 timeout);
 
     [CallWith=ScriptState] any getSyncParameter(WebGLSync? sync, GLenum pname);