Initial import attempt, just to play with. Many things disabled/removed

ui/cc/ThrottledTextureUploader.cpp

Index: ui/cc/ThrottledTextureUploader.cpp
diff --git a/ui/cc/ThrottledTextureUploader.cpp b/ui/cc/ThrottledTextureUploader.cpp
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index 0000000000000000000000000000000000000000..ed2d62648a8c6334d3112f1d81898018684186ed
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+++ b/ui/cc/ThrottledTextureUploader.cpp
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+/*
+ * Copyright (C) 2012, Google 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
+ *     documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+
+#include "ThrottledTextureUploader.h"
+
+#include "Extensions3DChromium.h"
+#include <public/WebGraphicsContext3D.h>
+
+namespace {
+
+// Number of pending texture update queries to allow.
+static const size_t maxPendingQueries = 2;
+
+} // anonymous namespace
+
+namespace WebCore {
+
+ThrottledTextureUploader::Query::Query(WebKit::WebGraphicsContext3D* context)
+    : m_context(context)
+    , m_queryId(0)
+{
+    m_queryId = m_context->createQueryEXT();
+}
+
+ThrottledTextureUploader::Query::~Query()
+{
+    m_context->deleteQueryEXT(m_queryId);
+}
+
+void ThrottledTextureUploader::Query::begin()
+{
+    m_context->beginQueryEXT(GL_COMMANDS_ISSUED_CHROMIUM, m_queryId);
+}
+
+void ThrottledTextureUploader::Query::end()
+{
+    m_context->endQueryEXT(GL_COMMANDS_ISSUED_CHROMIUM);
+}
+
+bool ThrottledTextureUploader::Query::isPending()
+{
+    unsigned available = 1;
+    m_context->getQueryObjectuivEXT(m_queryId, GL_QUERY_RESULT_AVAILABLE_EXT, &available);
+    return !available;
+}
+
+void ThrottledTextureUploader::Query::wait()
+{
+    unsigned result;
+    m_context->getQueryObjectuivEXT(m_queryId, GL_QUERY_RESULT_EXT, &result);
+}
+
+ThrottledTextureUploader::ThrottledTextureUploader(WebKit::WebGraphicsContext3D* context)
+    : m_context(context)
+    , m_maxPendingQueries(maxPendingQueries)
+{
+}
+
+ThrottledTextureUploader::ThrottledTextureUploader(WebKit::WebGraphicsContext3D* context, size_t pendingUploadLimit)
+    : m_context(context)
+    , m_maxPendingQueries(pendingUploadLimit)
+{
+    ASSERT(m_context);
+}
+
+ThrottledTextureUploader::~ThrottledTextureUploader()
+{
+}
+
+bool ThrottledTextureUploader::isBusy()
+{
+    processQueries();
+
+    if (!m_availableQueries.isEmpty())
+        return false;
+
+    if (m_pendingQueries.size() == m_maxPendingQueries)
+        return true;
+
+    m_availableQueries.append(Query::create(m_context));
+    return false;
+}
+
+void ThrottledTextureUploader::beginUploads()
+{
+    // Wait for query to become available.
+    while (isBusy())
+        m_pendingQueries.first()->wait();
+
+    ASSERT(!m_availableQueries.isEmpty());
+    m_availableQueries.first()->begin();
+}
+
+void ThrottledTextureUploader::endUploads()
+{
+    m_availableQueries.first()->end();
+    m_pendingQueries.append(m_availableQueries.takeFirst());
+}
+
+void ThrottledTextureUploader::uploadTexture(CCGraphicsContext* context, LayerTextureUpdater::Texture* texture, TextureAllocator* allocator, const IntRect sourceRect, const IntRect destRect)
+{
+    texture->updateRect(context, allocator, sourceRect, destRect);
+}
+
+void ThrottledTextureUploader::processQueries()
+{
+    while (!m_pendingQueries.isEmpty()) {
+        if (m_pendingQueries.first()->isPending())
+            break;
+
+        m_availableQueries.append(m_pendingQueries.takeFirst());
+    }
+}
+
+}