cc: Route offscreen context creation for compositor to the browser.

ui/compositor/offscreen_context.h

+// Copyright (c) 2013 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.
+
+#ifndef UI_COMPOSITOR_OFFSCREEN_CONTEXT_H_
+#define UI_COMPOSITOR_OFFSCREEN_CONTEXT_H_
+
+#include "base/memory/scoped_ptr.h"
+#include "skia/ext/refptr.h"
+#include "third_party/WebKit/Source/Platform/chromium/public/WebGraphicsContext3D.h"
+#include "ui/compositor/compositor_export.h"
+
+class GrContext;
+
+namespace ui {
+class ContextFactory;
+class OffscreenContext;
+
+class COMPOSITOR_EXPORT OffscreenContextClient {
+ public:
+  virtual void DidLoseContext(OffscreenContext* offscreen_context) = 0;
+  virtual void DidCreateContext(OffscreenContext* offscreen_context,
+                                bool success) = 0;
+};
+
+// This class lazily creates an offscreen context and a GrContext that is
+// bounds to the offscreen context.
+class COMPOSITOR_EXPORT OffscreenContext
+    : public NON_EXPORTED_BASE(
+        WebKit::WebGraphicsContext3D::WebGraphicsContextLostCallback) {
+ public:
+  OffscreenContext(
+      ui::ContextFactory* context_factory,
+      OffscreenContextClient* client);
+  virtual ~OffscreenContext();
+
+  WebKit::WebGraphicsContext3D* Context3d();
+  class GrContext* GrContext();
+
+ protected:
+  // The limit of the number of textures we hold in the GrContext's
+  // bitmap->texture cache.
+  static const int kMaxGaneshTextureCacheCount = 2048;
+  // The limit of the bytes allocated toward textures in the GrContext's
+  // bitmap->texture cache.
+  static const size_t kMaxGaneshTextureCacheBytes = 96 * 1024 * 1024;
+
+  WebKit::WebGraphicsContext3D* context3d_if_exists() const {
+    return context3d_.get();
+  }
+  class GrContext* gr_context_if_exists() const { return gr_context_.get(); }
+
+  virtual void DidCreateContext(bool success);
+
+ private:
+  // WebGraphicsContextLostCallback implementation.
+  virtual void onContextLost() OVERRIDE;
+
+  ui::ContextFactory* context_factory_;
+  OffscreenContextClient* client_;
+  scoped_ptr<WebKit::WebGraphicsContext3D> context3d_;
+  skia::RefPtr<class GrContext> gr_context_;
+};
+
+}  // namespace ui
+
+#endif  // UI_COMPOSITOR_OFFSCREEN_CONTEXT_H_