Make WebGL extensions get lost when context is lost.

Source/core/html/canvas/WebGLDebugShaders.cpp

Index: Source/core/html/canvas/WebGLDebugShaders.cpp
diff --git a/Source/core/html/canvas/WebGLDebugShaders.cpp b/Source/core/html/canvas/WebGLDebugShaders.cpp
index 9adcfa15b91286aa7bf25a1825fd0effb2ecb81d..ea33aa231f4e078d9ace9e2e9cd09697297927f1 100644
--- a/Source/core/html/canvas/WebGLDebugShaders.cpp
+++ b/Source/core/html/canvas/WebGLDebugShaders.cpp
@@ -50,15 +50,15 @@ WebGLExtension::ExtensionName WebGLDebugShaders::getName() const
     return WebGLDebugShadersName;
 }
 
-PassOwnPtr<WebGLDebugShaders> WebGLDebugShaders::create(WebGLRenderingContext* context)
+PassRefPtr<WebGLDebugShaders> WebGLDebugShaders::create(WebGLRenderingContext* context)
 {
-    return adoptPtr(new WebGLDebugShaders(context));
+    return adoptRef(new WebGLDebugShaders(context));
 }
 
 String WebGLDebugShaders::getTranslatedShaderSource(WebGLShader* shader, ExceptionCode& ec)
 {
     UNUSED_PARAM(ec);
-    if (m_context->isContextLost())
+    if (isLost())
         return String();
     if (!m_context->validateWebGLObject("getTranslatedShaderSource", shader))
         return "";