Fix WebGL context restoration logic. The retry mechanism was broken when the ownership of the WebGr…

Source/platform/graphics/gpu/Extensions3DUtil.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "platform/graphics/gpu/Extensions3DUtil.h"
 
 #include "public/platform/WebGraphicsContext3D.h"
 #include "wtf/text/CString.h"
 #include "wtf/text/StringHash.h"
 
 namespace WebCore {
 
 namespace {
 
 void splitStringHelper(const String& str, HashSet<String>& set)
 {
     Vector<String> substrings;
     str.split(" ", substrings);
     for (size_t i = 0; i < substrings.size(); ++i)
         set.add(substrings[i]);
 }
 
 } // anonymous namespace
 
+PassOwnPtr<Extensions3DUtil> Extensions3DUtil::create(blink::WebGraphicsContext3D* context)
+{
+    OwnPtr<Extensions3DUtil> out = adoptPtr(new Extensions3DUtil(context));
+    if (!out->initializeExtensions())
+        return nullptr;
+    return out.release();
+}
+
 Extensions3DUtil::Extensions3DUtil(blink::WebGraphicsContext3D* context)
     : m_context(context)
 {
-    initializeExtensions();
 }
 
 Extensions3DUtil::~Extensions3DUtil()
 {
 }
 
-void Extensions3DUtil::initializeExtensions()
+bool Extensions3DUtil::initializeExtensions()
 {
-    bool success = m_context->makeContextCurrent();
-    ASSERT(success);
-    if (!success)
-        return;
+    if (!m_context->makeContextCurrent()) {
+        // Most likely the GPU process exited and the attempt to reconnect to it failed.
+        // Need to try to restore the context again later.
+        return false;
+    }
+
+    if (m_context->isContextLost()) {
+        // Need to try to restore the context again later.
+        return false;
+    }
 
     String extensionsString = m_context->getString(GL_EXTENSIONS);
     splitStringHelper(extensionsString, m_enabledExtensions);
 
     String requestableExtensionsString = m_context->getRequestableExtensionsCHROMIUM();
     splitStringHelper(requestableExtensionsString, m_requestableExtensions);
+
+    return true;
 }
 
 
 bool Extensions3DUtil::supportsExtension(const String& name)
 {
     return m_enabledExtensions.contains(name) || m_requestableExtensions.contains(name);
 }
 
 bool Extensions3DUtil::ensureExtensionEnabled(const String& name)
 {
@@ skipping 19 matching lines @@
     // FIXME: restriction of (RGB || RGBA)/UNSIGNED_BYTE/(Level 0) should be lifted when
     // WebGraphicsContext3D::copyTextureCHROMIUM(...) are fully functional.
     if ((destFormat == GL_RGB || destFormat == GL_RGBA)
         && destType == GL_UNSIGNED_BYTE
         && !level)
         return true;
     return false;
 }
 
 } // namespace WebCore