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

content/common/gpu/client/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 CONTENT_COMMON_GPU_CLIENT_OFFSCREEN_CONTEXT_H_
+#define CONTENT_COMMON_GPU_CLIENT_OFFSCREEN_CONTEXT_H_
+
+#include "base/memory/scoped_ptr.h"
+#include "skia/ext/refptr.h"
+#include "third_party/WebKit/Source/Platform/chromium/public/WebGraphicsContext3D.h"
+
+class GrContext;
+
+namespace content {
+class OffscreenContext;
+
+class OffscreenContextClient {
+ public:
+  virtual WebKit::WebGraphicsContext3D* CreateOffscreenContext() = 0;
+
+  virtual void DidLoseContext(OffscreenContext* offscreen_context) = 0;
+  virtual void DidCreateContext(OffscreenContext* offscreen_context,
+                                bool success) = 0;
+};
+
+// This class lazily creates an offscreen GrContext that is bound to an
+// offscreen context lazily created by its subclass implementation.
+class OffscreenContext
+    : public WebKit::WebGraphicsContext3D::WebGraphicsContextLostCallback,
+      public WebKit::WebGraphicsContext3D::
+          WebGraphicsMemoryAllocationChangedCallbackCHROMIUM {
+ public:
+  explicit OffscreenContext(OffscreenContextClient* client);
+  virtual ~OffscreenContext();
+
+  WebKit::WebGraphicsContext3D* Context3d();
+  class GrContext* GrContext();
+
+ protected:
+  void SetGaneshContextMemoryLimit(bool nonzero_allocation);
+
+ private:
+  // WebGraphicsContextLostCallback implementation.
+  virtual void onContextLost() OVERRIDE;
+  // WebGraphicsMemoryAllocationChangedCallbackCHROMIUM implementation.
+  virtual void onMemoryAllocationChanged(
+      WebKit::WebGraphicsMemoryAllocation allocation) OVERRIDE;
+
+  // 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;
+
+  OffscreenContextClient* client_;
+  scoped_ptr<WebKit::WebGraphicsContext3D> context3d_;
+  skia::RefPtr<class GrContext> gr_context_;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_COMMON_GPU_CLIENT_OFFSCREEN_CONTEXT_H_