Change WebGL API arg nullable behavior.

third_party/WebKit/Source/modules/webgl/WebGL2RenderingContextBase.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/WebGL2RenderingContextBase.h"
 
 #include "bindings/modules/v8/WebGLAny.h"
 #include "core/dom/DOMException.h"
 #include "core/frame/ImageBitmap.h"
 #include "core/html/HTMLCanvasElement.h"
@@ skipping 2797 matching lines @@
 
 GLboolean WebGL2RenderingContextBase::isQuery(WebGLQuery* query) {
   if (isContextLost() || !query)
     return 0;
 
   return contextGL()->IsQueryEXT(query->object());
 }
 
 void WebGL2RenderingContextBase::beginQuery(GLenum target, WebGLQuery* query) {
   bool deleted;
-  if (!query) {
-    synthesizeGLError(GL_INVALID_OPERATION, "beginQuery",
-                      "query object is null");
-    return;
-  }
-
+  DCHECK(query);
   if (!checkObjectToBeBound("beginQuery", query, deleted))
     return;
   if (deleted) {
     synthesizeGLError(GL_INVALID_OPERATION, "beginQuery",
                       "attempted to begin a deleted query object");
     return;
   }
 
   if (query->getTarget() && query->getTarget() != target) {
     synthesizeGLError(GL_INVALID_OPERATION, "beginQuery",
@@ skipping 139 matching lines @@
       synthesizeGLError(GL_INVALID_ENUM, "getQuery", "invalid target");
       return ScriptValue::createNull(scriptState);
   }
   return ScriptValue::createNull(scriptState);
 }
 
 ScriptValue WebGL2RenderingContextBase::getQueryParameter(
     ScriptState* scriptState,
     WebGLQuery* query,
     GLenum pname) {
+  DCHECK(query);

[Ken Russell (switch to Gerrit), 2016/11/05 05:14:52]

It's pretty cool and interesting that because the DCHECK was added to
validateWebGLObject that the object is non-null, that very few changes had to be
made to WebGLRenderingContextBase and WebGL2RenderingContextBase to assert the
arguments were non-null.

   bool deleted;
-  if (!query) {
-    synthesizeGLError(GL_INVALID_OPERATION, "getQueryParameter",
-                      "query object is null");
-    return ScriptValue::createNull(scriptState);
-  }
   if (!checkObjectToBeBound("getQueryParameter", query, deleted))
     return ScriptValue::createNull(scriptState);
   if (deleted) {
     synthesizeGLError(GL_INVALID_OPERATION, "getQueryParameter",
                       "attempted to access to a deleted query object");
     return ScriptValue::createNull(scriptState);
   }
 
   // Query is non-null at this point.
   if (!query->getTarget()) {
@@ skipping 1962 matching lines @@
 
 void WebGL2RenderingContextBase::
     DrawingBufferClientRestorePixelUnpackBufferBinding() {
   if (!contextGL())
     return;
   contextGL()->BindBuffer(GL_PIXEL_UNPACK_BUFFER,
                           objectOrZero(m_boundPixelUnpackBuffer.get()));
 }
 
 }  // namespace blink