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

content/common/gpu/gpu_memory_manager.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_MANAGER_H_
 #define CONTENT_COMMON_GPU_GPU_MEMORY_MANAGER_H_
 #pragma once
 
 #if defined(ENABLE_GPU)
 
@@ skipping 10 matching lines @@
   virtual ~GpuMemoryManagerClient() {}
 
   virtual void AppendAllCommandBufferStubs(
       std::vector<GpuCommandBufferStubBase*>& stubs) = 0;
 };
 
 class CONTENT_EXPORT GpuMemoryManager {
  public:
   enum { kDefaultMaxSurfacesWithFrontbufferSoftLimit = 8 };
 
+  // These are predefined values (in bytes) for
+  // GpuMemoryAllocation::gpuResourceSizeInBytes.
+  // Maximum Allocation for all tabs is a soft limit that can be exceeded
+  // during the time it takes for renderers to respect new allocations,
+  // including when switching tabs or opening a new window.
+  // To alleviate some pressure, we decrease our desired limit by "one tabs'
+  // worth" of memory.
+  enum {
+#if defined(OS_ANDROID)
+    kMinimumAllocationForTab = 32 * 1024 * 1024,
+    kMaximumAllocationForTabs = 64 * 1024 * 1024,
+#else
+    kMinimumAllocationForTab = 64 * 1024 * 1024,
+    kMaximumAllocationForTabs = 512 * 1024 * 1024 - kMinimumAllocationForTab,
+#endif
+  };
+
   GpuMemoryManager(GpuMemoryManagerClient* client,
                    size_t max_surfaces_with_frontbuffer_soft_limit);
   ~GpuMemoryManager();
 
   void ScheduleManage();
 
  private:
   friend class GpuMemoryManagerTest;
   void Manage();
 
   class CONTENT_EXPORT StubWithSurfaceComparator {
    public:
     bool operator()(GpuCommandBufferStubBase* lhs,
                     GpuCommandBufferStubBase* rhs);
   };
 
   GpuMemoryManagerClient* client_;
   bool manage_scheduled_;
   size_t max_surfaces_with_frontbuffer_soft_limit_;
   base::WeakPtrFactory<GpuMemoryManager> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(GpuMemoryManager);
 };
 
 #endif
 
 #endif // CONTENT_COMMON_GPU_GPU_MEMORY_MANAGER_H_