Oilpan: unbreak WebGL context lost tests following r190259.

Source/core/html/canvas/WebGLRenderingContextBase.cpp

 /*
  * Copyright (C) 2009 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 2233 matching lines @@
 
 bool WebGLRenderingContextBase::extensionSupportedAndAllowed(const ExtensionTracker* tracker)
 {
     if (tracker->draft() && !RuntimeEnabledFeatures::webGLDraftExtensionsEnabled())
         return false;
     if (!tracker->supported(this))
         return false;
     return true;
 }
 
-
 ScriptValue WebGLRenderingContextBase::getExtension(ScriptState* scriptState, const String& name)
 {
-    RefPtrWillBeRawPtr<WebGLExtension> extension;
+    RefPtrWillBeRawPtr<WebGLExtension> extension = nullptr;
 
     if (!isContextLost()) {
         for (size_t i = 0; i < m_extensions.size(); ++i) {
             ExtensionTracker* tracker = m_extensions[i].get();
             if (tracker->matchesNameWithPrefixes(name)) {
                 if (extensionSupportedAndAllowed(tracker)) {
                     extension = tracker->getExtension(this);
                     if (extension)
                         m_extensionEnabled[extension->name()] = true;
                 }
@@ skipping 3769 matching lines @@
     return m_sharedWebGraphicsContext3D ? m_sharedWebGraphicsContext3D->drawingBuffer() : 0;
 }
 #else
 DrawingBuffer* WebGLRenderingContextBase::drawingBuffer() const
 {
     return m_drawingBuffer.get();
 }
 #endif
 
 } // namespace blink