GpuMemoryManager suggests values for renderer Contents Texture Managers' preferred memory limit.

content/common/gpu/gpu_memory_allocation.h

 // Copyright (c) 2012 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_GPU_MEMORY_ALLOCATION_H_
 #define CONTENT_COMMON_GPU_GPU_MEMORY_ALLOCATION_H_
 #pragma once
 
 #include "base/basictypes.h"
 
 // These are per context memory allocation limits set by the GpuMemoryManager
 // and assigned to the browser and renderer context.
 // They will change over time, given memory availability, and browser state.
 
-
 // Memory Allocation which will be assigned to the renderer context.
 struct GpuMemoryAllocationForRenderer {
   enum {
     INVALID_RESOURCE_SIZE = -1
   };
 
   // Exceeding this limit for an unreasonable amount of time may cause context
   // to be lost.
   size_t gpu_resource_size_in_bytes;
   bool suggest_have_backbuffer;
@@ skipping 35 matching lines @@
   }
   bool operator!=(const GpuMemoryAllocationForBrowser& other) const {
     return !(*this == other);
   }
 };
 
 // Combination of the above two Memory Allocations which will be created by the
 // GpuMemoryManager.
 struct GpuMemoryAllocation : public GpuMemoryAllocationForRenderer,
                              public GpuMemoryAllocationForBrowser {
+  // Bitmap
+  enum BufferAllocation {
+    kHasNoBuffers = 0,
+    kHasFrontbuffer = 1,
+    kHasBackbuffer = 2
+  };
+
   GpuMemoryAllocation()
       : GpuMemoryAllocationForRenderer(),
         GpuMemoryAllocationForBrowser() {
   }
 
   GpuMemoryAllocation(size_t gpu_resource_size_in_bytes,
                       bool suggest_have_backbuffer,
                       bool suggest_have_frontbuffer)
       : GpuMemoryAllocationForRenderer(gpu_resource_size_in_bytes,
                                        suggest_have_backbuffer),
         GpuMemoryAllocationForBrowser(suggest_have_frontbuffer) {
   }
 
+  GpuMemoryAllocation(size_t gpu_resource_size_in_bytes,
+                      int allocationBitmap)
+      : GpuMemoryAllocationForRenderer(gpu_resource_size_in_bytes,
+                                       allocationBitmap & kHasBackbuffer),
+        GpuMemoryAllocationForBrowser(allocationBitmap & kHasFrontbuffer) {
+  }
+
   bool operator==(const GpuMemoryAllocation& other) const {
       return static_cast<const GpuMemoryAllocationForRenderer&>(*this) ==
              static_cast<const GpuMemoryAllocationForRenderer&>(other) &&
              static_cast<const GpuMemoryAllocationForBrowser&>(*this) ==
              static_cast<const GpuMemoryAllocationForBrowser&>(other);
   }
   bool operator!=(const GpuMemoryAllocation& other) const {
     return !(*this == other);
   }
 };
 
 #endif // CONTENT_COMMON_GPU_GPU_MEMORY_ALLOCATION_H_