Remove methods from WebGraphicsContext3D that wrap type casts.

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

Index: third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp
diff --git a/third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp b/third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp
index b62b7d4da07522baeaa88b20bec994b1d701239d..b92a8c47b00e37c940cdf74130811439a815872b 100644
--- a/third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp
+++ b/third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp
@@ -2130,7 +2130,7 @@ void WebGLRenderingContextBase::drawElements(GLenum mode, GLsizei count, GLenum
     }
 
     clearIfComposited();
-    webContext()->drawElements(mode, count, type, static_cast<GLintptr>(offset));
+    contextGL()->DrawElements(mode, count, type, reinterpret_cast<void*>(static_cast<intptr_t>(offset)));
     markContextChanged(CanvasChanged);
 }
 
@@ -3292,8 +3292,11 @@ long long WebGLRenderingContextBase::getVertexAttribOffset(GLuint index, GLenum
 {
     if (isContextLost())
         return 0;
-    GLintptr result = webContext()->getVertexAttribOffset(index, pname);
-    return static_cast<long long>(result);
+    GLvoid* result = nullptr;
+    // NOTE: If pname is ever a value that returns more then 1 element
+    // this will corrupt memory.
+    contextGL()->GetVertexAttribPointerv(index, pname, &result);
+    return static_cast<long long>(reinterpret_cast<intptr_t>(result));
 }
 
 void WebGLRenderingContextBase::hint(GLenum target, GLenum mode)
@@ -4950,7 +4953,7 @@ void WebGLRenderingContextBase::vertexAttribPointer(ScriptState* scriptState, GL
     }
 
     m_boundVertexArrayObject->setArrayBufferForAttrib(index, m_boundArrayBuffer.get());
-    webContext()->vertexAttribPointer(index, size, type, normalized, stride, static_cast<GLintptr>(offset));
+    contextGL()->VertexAttribPointer(index, size, type, normalized, stride, reinterpret_cast<void*>(static_cast<intptr_t>(offset)));
     maybePreserveDefaultVAOObjectWrapper(scriptState);
     preserveObjectWrapper(scriptState, m_boundVertexArrayObject, "arraybuffer", index, m_boundArrayBuffer);
 }