Change WebGL API arg nullable behavior.

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

Index: third_party/WebKit/Source/modules/webgl/WebGL2RenderingContextBase.cpp
diff --git a/third_party/WebKit/Source/modules/webgl/WebGL2RenderingContextBase.cpp b/third_party/WebKit/Source/modules/webgl/WebGL2RenderingContextBase.cpp
index 97d8f1c1a0c67d456beb5a4108fa5da17dfc61dd..b1cfe9ebbed5c87bc3ff8c02ebeb92e8b6e6bd5d 100644
--- a/third_party/WebKit/Source/modules/webgl/WebGL2RenderingContextBase.cpp
+++ b/third_party/WebKit/Source/modules/webgl/WebGL2RenderingContextBase.cpp
@@ -2815,12 +2815,7 @@ GLboolean WebGL2RenderingContextBase::isQuery(WebGLQuery* query) {
 
 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) {
@@ -2980,12 +2975,8 @@ 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) {