Speed up fix for expando-loss conformance test.

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

 /*
  * 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 1021 matching lines @@
     void restoreCurrentTexture2D();
 
     void findNewMaxNonDefaultTextureUnit();
 
     virtual void renderbufferStorageImpl(GLenum target, GLsizei samples, GLenum internalformat, GLsizei width, GLsizei height, const char* functionName);
 
     // Ensures that the JavaScript wrappers for objects that are
     // latched into the context's state, or which are implicitly
     // linked together (like programs and their attached shaders), are
     // not garbage collected before they should be.
-    static void preserveObjectWrapper(ScriptState*, ScriptWrappable* sourceObject, const char* baseName, unsigned long index, ScriptWrappable* targetObject);
+    v8::Persistent<v8::Array> m_2DTextureWrappers;
+    v8::Persistent<v8::Array> m_2DArrayTextureWrappers;
+    v8::Persistent<v8::Array> m_3DTextureWrappers;
+    v8::Persistent<v8::Array> m_cubeMapTextureWrappers;
+    v8::Persistent<v8::Array> m_extensionWrappers;

[haraken, 2016/05/13 01:32:41]

Would you help me understand why these persistent handles don't cause leaks?

[Ken Russell (switch to Gerrit), 2016/05/13 01:45:35]

I specifically made them weak to avoid possible leaks. See the call to SetWeak
in WebGLRenderingContextBase::preserveObjectWrapper.

+
+    // The "catch-all" array for the rest of the preserved object
+    // wrappers. The enum below defines how the indices in this array
+    // are used.
+    enum PreservedWrapperIndex {
+        PreservedArrayBuffer,
+        PreservedElementArrayBuffer,
+        PreservedFramebuffer,
+        PreservedProgram,
+        PreservedRenderbuffer,
+        PreservedDefaultVAO,
+        PreservedVAO,
+    };
+    v8::Persistent<v8::Array> m_miscWrappers;
+
+    static void preserveObjectWrapper(ScriptState*, ScriptWrappable* sourceObject, v8::Local<v8::String> hiddenValueName, v8::Persistent<v8::Array>* persistentCache, uint32_t index, ScriptWrappable* targetObject);
+
     // Called to lazily instantiate the wrapper for the default VAO
     // during calls to bindBuffer and vertexAttribPointer (from
     // JavaScript).
     void maybePreserveDefaultVAOObjectWrapper(ScriptState*);
 
     virtual bool transformFeedbackActive() const { return false; }
     virtual bool transformFeedbackPaused() const { return false; }
 
     friend class WebGLStateRestorer;
     friend class WebGLRenderingContextEvictionManager;
@@ skipping 19 matching lines @@
     static PassOwnPtr<WebGraphicsContext3DProvider> createContextProviderOnWorkerThread(Platform::ContextAttributes, Platform::GraphicsInfo, ScriptState*);
 };
 
 DEFINE_TYPE_CASTS(WebGLRenderingContextBase, CanvasRenderingContext, context, context->is3d(), context.is3d());
 
 } // namespace blink
 
 WTF_ALLOW_MOVE_INIT_AND_COMPARE_WITH_MEM_FUNCTIONS(blink::WebGLRenderingContextBase::TextureUnitState);
 
 #endif // WebGLRenderingContextBase_h