Defer WebGL lost context restore until visible.

third_party/WebKit/Source/modules/webgl/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 815 matching lines @@
         return true;
     default:
         return false;
     }
 }
 
 } // namespace
 
 WebGLRenderingContextBase::WebGLRenderingContextBase(HTMLCanvasElement* passedCanvas, PassOwnPtr<WebGraphicsContext3D> context, const WebGLContextAttributes& requestedAttributes)
     : CanvasRenderingContext(passedCanvas)
+    , m_isHidden(false)
     , m_contextLostMode(NotLostContext)
     , m_autoRecoveryMethod(Manual)
     , m_dispatchContextLostEventTimer(this, &WebGLRenderingContextBase::dispatchContextLostEvent)
     , m_restoreAllowed(false)
     , m_restoreTimer(this, &WebGLRenderingContextBase::maybeRestoreContext)
     , m_preservedDefaultVAOObjectWrapper(false)
     , m_generatedImageCache(4)
     , m_requestedAttributes(requestedAttributes)
     , m_synthesizedErrorsToConsole(true)
     , m_numGLErrorsToConsoleAllowed(maxGLErrorsAllowedToConsole)
@@ skipping 361 matching lines @@
 }
 
 void WebGLRenderingContextBase::markLayerComposited()
 {
     if (!isContextLost())
         drawingBuffer()->setBufferClearNeeded(true);
 }
 
 void WebGLRenderingContextBase::setIsHidden(bool hidden)
 {
+    m_isHidden = hidden;
     if (drawingBuffer())
         drawingBuffer()->setIsHidden(hidden);
+
+    if (!hidden && isContextLost() && m_restoreAllowed && m_autoRecoveryMethod == Auto) {
+        ASSERT(!m_restoreTimer.isActive());
+        m_restoreTimer.startOneShot(0, BLINK_FROM_HERE);
+    }
 }
 
 bool WebGLRenderingContextBase::paintRenderingResultsToCanvas(SourceDrawingBuffer sourceBuffer)
 {
     if (isContextLost())
         return false;
 
     bool mustClearNow = clearIfComposited() != Skipped;
     if (!m_markedCanvasDirty && !mustClearNow)
         return false;
@@ skipping 4665 matching lines @@
     }
 
     return true;
 }
 
 void WebGLRenderingContextBase::dispatchContextLostEvent(Timer<WebGLRenderingContextBase>*)
 {
     RefPtrWillBeRawPtr<WebGLContextEvent> event = WebGLContextEvent::create(EventTypeNames::webglcontextlost, false, true, "");
     canvas()->dispatchEvent(event);
     m_restoreAllowed = event->defaultPrevented();
-    if (m_restoreAllowed) {
+    if (m_restoreAllowed && !m_isHidden) {
         if (m_autoRecoveryMethod == Auto)
             m_restoreTimer.startOneShot(0, BLINK_FROM_HERE);
     }
 }
 
 void WebGLRenderingContextBase::maybeRestoreContext(Timer<WebGLRenderingContextBase>*)
 {
     ASSERT(isContextLost());
 
     // The rendering context is not restored unless the default behavior of the
@@ skipping 363 matching lines @@
         webContext()->pixelStorei(GL_UNPACK_ALIGNMENT, 1);
 }
 
 void WebGLRenderingContextBase::restoreUnpackParameters()
 {
     if (m_unpackAlignment != 1)
         webContext()->pixelStorei(GL_UNPACK_ALIGNMENT, m_unpackAlignment);
 }
 
 } // namespace blink